David Woodhouse [Tue, 2 Nov 2021 17:36:39 +0000 (17:36 +0000)]
KVM: x86: Fix recording of guest steal time / preempted status
In commit 33bbbb26fbdc ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is
not missed") we switched to using a gfn_to_pfn_cache for accessing the
guest steal time structure in order to allow for an atomic xchg of the
preempted field. This has a couple of problems.
Firstly, kvm_map_gfn() doesn't work at all for IOMEM pages when the
atomic flag is set, which it is in kvm_steal_time_set_preempted(). So a
guest vCPU using an IOMEM page for its steal time would never have its
preempted field set.
Secondly, the gfn_to_pfn_cache is not invalidated in all cases where it
should have been. There are two stages to the GFN->PFN conversion;
first the GFN is converted to a userspace HVA, and then that HVA is
looked up in the process page tables to find the underlying host PFN.
Correct invalidation of the latter would require being hooked up to the
MMU notifiers, but that doesn't happen---so it just keeps mapping and
unmapping the *wrong* PFN after the userspace page tables change.
In the !IOMEM case at least the stale page *is* pinned all the time it's
cached, so it won't be freed and reused by anyone else while still
receiving the steal time updates. The map/unmap dance only takes care
of the KVM administrivia such as marking the page dirty.
Until the gfn_to_pfn cache handles the remapping automatically by
integrating with the MMU notifiers, we might as well not get a
kernel mapping of it, and use the perfectly serviceable userspace HVA
that we already have. We just need to implement the atomic xchg on
the userspace address with appropriate exception handling, which is
fairly trivial.
Cc: stable@vger.kernel.org Fixes: 33bbbb26fbdc ("x86/KVM: Make sure KVM_VCPU_FLUSH_TLB flag is not missed") Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <3645b9b889dac6438394194bb5586a46b68d581f.camel@infradead.org>
[I didn't entirely agree with David's assessment of the
usefulness of the gfn_to_pfn cache, and integrated the outcome
of the discussion in the above commit message. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bixuan Cui [Wed, 27 Oct 2021 07:20:53 +0000 (15:20 +0800)]
RISC-V: KVM: fix boolreturn.cocci warnings
Fix boolreturn.cocci warnings:
./arch/riscv/kvm/mmu.c:603:9-10: WARNING: return of 0/1 in function
'kvm_age_gfn' with return type bool
./arch/riscv/kvm/mmu.c:582:9-10: WARNING: return of 0/1 in function
'kvm_set_spte_gfn' with return type bool
./arch/riscv/kvm/mmu.c:621:9-10: WARNING: return of 0/1 in function
'kvm_test_age_gfn' with return type bool
./arch/riscv/kvm/mmu.c:568:9-10: WARNING: return of 0/1 in function
'kvm_unmap_gfn_range' with return type bool
Signed-off-by: Bixuan Cui <cuibixuan@linux.alibaba.com> Signed-off-by: Anup Patel <anup.patel@wdc.com>
Anup Patel [Tue, 26 Oct 2021 17:01:36 +0000 (22:31 +0530)]
RISC-V: KVM: Fix GPA passed to __kvm_riscv_hfence_gvma_xyz() functions
The parameter passed to HFENCE.GVMA instruction in rs1 register
is guest physical address right shifted by 2 (i.e. divided by 4).
Unfortunately, we overlooked the semantics of rs1 registers for
HFENCE.GVMA instruction and never right shifted guest physical
address by 2. This issue did not manifest for hypervisors till
now because:
1) Currently, only __kvm_riscv_hfence_gvma_all() and SBI
HFENCE calls are used to invalidate TLB.
2) All H-extension implementations (such as QEMU, Spike,
Rocket Core FPGA, etc) that we tried till now were
conservatively flushing everything upon any HFENCE.GVMA
instruction.
This patch fixes GPA passed to __kvm_riscv_hfence_gvma_vmid_gpa()
and __kvm_riscv_hfence_gvma_gpa() functions.
Collin Walling [Wed, 27 Oct 2021 02:54:51 +0000 (22:54 -0400)]
KVM: s390: add debug statement for diag 318 CPNC data
The diag 318 data contains values that denote information regarding the
guest's environment. Currently, it is unecessarily difficult to observe
this value (either manually-inserted debug statements, gdb stepping, mem
dumping etc). It's useful to observe this information to obtain an
at-a-glance view of the guest's environment, so lets add a simple VCPU
event that prints the CPNC to the s390dbf logs.
Signed-off-by: Collin Walling <walling@linux.ibm.com> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com> Link: https://lore.kernel.org/r/20211027025451.290124-1-walling@linux.ibm.com
[borntraeger@de.ibm.com]: change debug level to 3 Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
KVM: s390: pv: properly handle page flags for protected guests
Introduce variants of the convert and destroy page functions that also
clear the PG_arch_1 bit used to mark them as secure pages.
The PG_arch_1 flag is always allowed to overindicate; using the new
functions introduced here allows to reduce the extent of overindication
and thus improve performance.
These new functions can only be called on pages for which a reference
is already being held.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Link: https://lore.kernel.org/r/20210920132502.36111-7-imbrenda@linux.ibm.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
If handle_sske cannot set the storage key, because there is no
page table entry or no present large page entry, it calls
fixup_user_fault.
However, currently, if the call succeeds, handle_sske returns
-EAGAIN, without having set the storage key.
Instead, retry by continue'ing the loop without incrementing the
address.
The same issue in handle_pfmf was fixed by 10c0728d6032 ("KVM: s390: Fix pfmf and conditional skey emulation").
Paolo Bonzini [Mon, 25 Oct 2021 12:39:43 +0000 (08:39 -0400)]
Merge branch 'kvm-pvclock-raw-spinlock' into HEAD
pvclock_gtod_sync_lock is completely gone in Linux 5.16. Include this
fix into the kvm/next history to record that the syzkaller report is
not valid there.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
David Woodhouse [Sat, 23 Oct 2021 20:29:22 +0000 (21:29 +0100)]
KVM: x86: switch pvclock_gtod_sync_lock to a raw spinlock
On the preemption path when updating a Xen guest's runstate times, this
lock is taken inside the scheduler rq->lock, which is a raw spinlock.
This was shown in a lockdep warning:
[ 89.138354] =============================
[ 89.138356] [ BUG: Invalid wait context ]
[ 89.138358] 5.15.0-rc5+ #834 Tainted: G S I E
[ 89.138360] -----------------------------
[ 89.138361] xen_shinfo_test/2575 is trying to lock:
[ 89.138363] ffffa34a0364efd8 (&kvm->arch.pvclock_gtod_sync_lock){....}-{3:3}, at: get_kvmclock_ns+0x1f/0x130 [kvm]
[ 89.138442] other info that might help us debug this:
[ 89.138444] context-{5:5}
[ 89.138445] 4 locks held by xen_shinfo_test/2575:
[ 89.138447] #0: ffff972bdc3b8108 (&vcpu->mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x77/0x6f0 [kvm]
[ 89.138483] #1: ffffa34a03662e90 (&kvm->srcu){....}-{0:0}, at: kvm_arch_vcpu_ioctl_run+0xdc/0x8b0 [kvm]
[ 89.138526] #2: ffff97331fdbac98 (&rq->__lock){-.-.}-{2:2}, at: __schedule+0xff/0xbd0
[ 89.138534] #3: ffffa34a03662e90 (&kvm->srcu){....}-{0:0}, at: kvm_arch_vcpu_put+0x26/0x170 [kvm]
...
[ 89.138695] get_kvmclock_ns+0x1f/0x130 [kvm]
[ 89.138734] kvm_xen_update_runstate+0x14/0x90 [kvm]
[ 89.138783] kvm_xen_update_runstate_guest+0x15/0xd0 [kvm]
[ 89.138830] kvm_arch_vcpu_put+0xe6/0x170 [kvm]
[ 89.138870] kvm_sched_out+0x2f/0x40 [kvm]
[ 89.138900] __schedule+0x5de/0xbd0
Cc: stable@vger.kernel.org Reported-by: syzbot+b282b65c2c68492df769@syzkaller.appspotmail.com Fixes: 652519a15a34 ("KVM: x86/xen: Add support for vCPU runstate information") Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Message-Id: <1b02a06421c17993df337493a68ba923f3bd5c0f.camel@infradead.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
David Edmondson [Mon, 20 Sep 2021 10:37:37 +0000 (11:37 +0100)]
KVM: x86: SGX must obey the KVM_INTERNAL_ERROR_EMULATION protocol
When passing the failing address and size out to user space, SGX must
ensure not to trample on the earlier fields of the emulation_failure
sub-union of struct kvm_run.
Signed-off-by: David Edmondson <david.edmondson@oracle.com> Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210920103737.2696756-5-david.edmondson@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
David Edmondson [Mon, 20 Sep 2021 10:37:36 +0000 (11:37 +0100)]
KVM: x86: On emulation failure, convey the exit reason, etc. to userspace
Should instruction emulation fail, include the VM exit reason, etc. in
the emulation_failure data passed to userspace, in order that the VMM
can report it as a debugging aid when describing the failure.
Suggested-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: David Edmondson <david.edmondson@oracle.com> Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210920103737.2696756-4-david.edmondson@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
David Edmondson [Mon, 20 Sep 2021 10:37:35 +0000 (11:37 +0100)]
KVM: x86: Get exit_reason as part of kvm_x86_ops.get_exit_info
Extend the get_exit_info static call to provide the reason for the VM
exit. Modify relevant trace points to use this rather than extracting
the reason in the caller.
Signed-off-by: David Edmondson <david.edmondson@oracle.com> Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210920103737.2696756-3-david.edmondson@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
David Edmondson [Mon, 20 Sep 2021 10:37:34 +0000 (11:37 +0100)]
KVM: x86: Clarify the kvm_run.emulation_failure structure layout
Until more flags for kvm_run.emulation_failure flags are defined, it
is undetermined whether new payload elements corresponding to those
flags will be additive or alternative. As a hint to userspace that an
alternative is possible, wrap the current payload elements in a union.
Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: David Edmondson <david.edmondson@oracle.com> Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210920103737.2696756-2-david.edmondson@oracle.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Eric Farman [Fri, 8 Oct 2021 20:31:12 +0000 (22:31 +0200)]
KVM: s390: Add a routine for setting userspace CPU state
This capability exists, but we don't record anything when userspace
enables it. Let's refactor that code so that a note can be made in
the debug logs that it was enabled.
Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20211008203112.1979843-7-farman@linux.ibm.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Eric Farman [Fri, 8 Oct 2021 20:31:07 +0000 (22:31 +0200)]
KVM: s390: Simplify SIGP Set Arch handling
The Principles of Operations describe the various reasons that
each individual SIGP orders might be rejected, and the status
bit that are set for each condition.
For example, for the Set Architecture order, it states:
"If it is not true that all other CPUs in the configu-
ration are in the stopped or check-stop state, ...
bit 54 (incorrect state) ... is set to one."
However, it also states:
"... if the CZAM facility is installed, ...
bit 55 (invalid parameter) ... is set to one."
Since the Configuration-z/Architecture-Architectural Mode (CZAM)
facility is unconditionally presented, there is no need to examine
each VCPU to determine if it is started/stopped. It can simply be
rejected outright with the Invalid Parameter bit.
Fixes: dd9fe807a7bb ("KVM: s390: Support Configuration z/Architecture Mode") Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Link: https://lore.kernel.org/r/20211008203112.1979843-2-farman@linux.ibm.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
KVM: s390: pv: avoid stalls when making pages secure
Improve make_secure_pte to avoid stalls when the system is heavily
overcommitted. This was especially problematic in kvm_s390_pv_unpack,
because of the loop over all pages that needed unpacking.
Due to the locks being held, it was not possible to simply replace
uv_call with uv_call_sched. A more complex approach was
needed, in which uv_call is replaced with __uv_call, which does not
loop. When the UVC needs to be executed again, -EAGAIN is returned, and
the caller (or its caller) will try again.
When -EAGAIN is returned, the path is the same as when the page is in
writeback (and the writeback check is also performed, which is
harmless).
Fixes: 7d6a1a50ffb9fb ("s390/mm: provide memory management functions for protected KVM guests") Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Link: https://lore.kernel.org/r/20210920132502.36111-5-imbrenda@linux.ibm.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
If kvm_s390_pv_destroy_cpu is called more than once, we risk calling
free_page on a random page, since the sidad field is aliased with the
gbea, which is not guaranteed to be zero.
This can happen, for example, if userspace calls the KVM_PV_DISABLE
IOCTL, and it fails, and then userspace calls the same IOCTL again.
This scenario is only possible if KVM has some serious bug or if the
hardware is broken.
The solution is to simply return successfully immediately if the vCPU
was already non secure.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Fixes: 511ead40324d7036649fae652be4b4c2304f35f0 ("KVM: S390: protvirt: Introduce instruction data area bounce buffer") Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Message-Id: <20210920132502.36111-3-imbrenda@linux.ibm.com> Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
s390/uv: fully validate the VMA before calling follow_page()
We should not walk/touch page tables outside of VMA boundaries when
holding only the mmap sem in read mode. Evil user space can modify the
VMA layout just before this function runs and e.g., trigger races with
page table removal code since commit 4dc981eb15b2 ("mm: mmap: zap pages
with read mmap_sem in munmap").
find_vma() does not check if the address is >= the VMA start address;
use vma_lookup() instead.
Fixes: 7d6a1a50ffb9 ("s390/mm: provide memory management functions for protected KVM guests") Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Link: https://lore.kernel.org/r/20210909162248.14969-6-david@redhat.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
s390/mm: fix VMA and page table handling code in storage key handling functions
There are multiple things broken about our storage key handling
functions:
1. We should not walk/touch page tables outside of VMA boundaries when
holding only the mmap sem in read mode. Evil user space can modify the
VMA layout just before this function runs and e.g., trigger races with
page table removal code since commit 4dc981eb15b2 ("mm: mmap: zap pages
with read mmap_sem in munmap"). gfn_to_hva() will only translate using
KVM memory regions, but won't validate the VMA.
2. We should not allocate page tables outside of VMA boundaries: if
evil user space decides to map hugetlbfs to these ranges, bad things
will happen because we suddenly have PTE or PMD page tables where we
shouldn't have them.
3. We don't handle large PUDs that might suddenly appeared inside our page
table hierarchy.
Don't manually allocate page tables, properly validate that we have VMA and
bail out on pud_large().
All callers of page table handling functions, except
get_guest_storage_key(), call fixup_user_fault() in case they
receive an -EFAULT and retry; this will allocate the necessary page tables
if required.
To keep get_guest_storage_key() working as expected and not requiring
kvm_s390_get_skeys() to call fixup_user_fault() distinguish between
"there is simply no page table or huge page yet and the key is assumed
to be 0" and "this is a fault to be reported".
Although commit fdbee320c5cf ("s390/mm: Add huge pmd storage key handling")
introduced most of the affected code, it was actually already broken
before when using get_locked_pte() without any VMA checks.
Note: Ever since commit fdbee320c5cf ("s390/mm: Add huge pmd storage key
handling") we can no longer set a guest storage key (for example from
QEMU during VM live migration) without actually resolving a fault.
Although we would have created most page tables, we would choke on the
!pmd_present(), requiring a call to fixup_user_fault(). I would
have thought that this is problematic in combination with postcopy life
migration ... but nobody noticed and this patch doesn't change the
situation. So maybe it's just fine.
Fixes: ad9c16cc99ec ("KVM: S390: Create helper function get_guest_storage_key") Fixes: 2170d70613b5 ("s390/kvm: Provide function for setting the guest storage key") Fixes: 8d7f36486e69 ("KVM: s390: handle missing storage-key facility") Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Link: https://lore.kernel.org/r/20210909162248.14969-5-david@redhat.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
s390/mm: validate VMA in PGSTE manipulation functions
We should not walk/touch page tables outside of VMA boundaries when
holding only the mmap sem in read mode. Evil user space can modify the
VMA layout just before this function runs and e.g., trigger races with
page table removal code since commit 4dc981eb15b2 ("mm: mmap: zap pages
with read mmap_sem in munmap"). gfn_to_hva() will only translate using
KVM memory regions, but won't validate the VMA.
Further, we should not allocate page tables outside of VMA boundaries: if
evil user space decides to map hugetlbfs to these ranges, bad things will
happen because we suddenly have PTE or PMD page tables where we
shouldn't have them.
Similarly, we have to check if we suddenly find a hugetlbfs VMA, before
calling get_locked_pte().
s390/gmap: don't unconditionally call pte_unmap_unlock() in __gmap_zap()
... otherwise we will try unlocking a spinlock that was never locked via a
garbage pointer.
At the time we reach this code path, we usually successfully looked up
a PGSTE already; however, evil user space could have manipulated the VMA
layout in the meantime and triggered removal of the page table.
We should not walk/touch page tables outside of VMA boundaries when
holding only the mmap sem in read mode. Evil user space can modify the
VMA layout just before this function runs and e.g., trigger races with
page table removal code since commit 4dc981eb15b2 ("mm: mmap: zap pages
with read mmap_sem in munmap"). The pure prescence in our guest_to_host
radix tree does not imply that there is a VMA.
Further, we should not allocate page tables (via get_locked_pte()) outside
of VMA boundaries: if evil user space decides to map hugetlbfs to these
ranges, bad things will happen because we suddenly have PTE or PMD page
tables where we shouldn't have them.
Similarly, we have to check if we suddenly find a hugetlbfs VMA, before
calling get_locked_pte().
Note that gmap_discard() is different:
zap_page_range()->unmap_single_vma() makes sure to stay within VMA
boundaries.
Fixes: 3d80b65cf27b ("s390/kvm: support collaborative memory management") Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> Link: https://lore.kernel.org/r/20210909162248.14969-2-david@redhat.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Jim Mattson [Thu, 30 Sep 2021 00:36:49 +0000 (17:36 -0700)]
KVM: selftests: Fix nested SVM tests when built with clang
Though gcc conveniently compiles a simple memset to "rep stos," clang
prefers to call the libc version of memset. If a test is dynamically
linked, the libc memset isn't available in L1 (nor is the PLT or the
GOT, for that matter). Even if the test is statically linked, the libc
memset may choose to use some CPU features, like AVX, which may not be
enabled in L1. Note that __builtin_memset doesn't solve the problem,
because (a) the compiler is free to call memset anyway, and (b)
__builtin_memset may also choose to use features like AVX, which may
not be available in L1.
To avoid a myriad of problems, use an explicit "rep stos" to clear the
VMCB in generic_svm_setup(), which is called both from L0 and L1.
Reported-by: Ricardo Koller <ricarkol@google.com> Signed-off-by: Jim Mattson <jmattson@google.com> Fixes: 2a43afbda49f3 ("selftests: KVM: AMD Nested test infrastructure")
Message-Id: <20210930003649.4026553-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jim Mattson [Thu, 21 Oct 2021 18:54:49 +0000 (11:54 -0700)]
kvm: x86: Remove stale declaration of kvm_no_apic_vcpu
This variable was renamed to kvm_has_noapic_vcpu in commit 8ae00f46d04d ("KVM: Stop using deprecated jump label APIs").
Signed-off-by: Jim Mattson <jmattson@google.com>
Message-Id: <20211021185449.3471763-1-jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM: VMX: Unregister posted interrupt wakeup handler on hardware unsetup
Unregister KVM's posted interrupt wakeup handler during unsetup so that a
spurious interrupt that arrives after kvm_intel.ko is unloaded doesn't
call into freed memory.
Fixes: 91154d85ff04 ("KVM: Update Posted-Interrupts Descriptor when vCPU is blocked") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211009001107.3936588-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86/irq: Ensure PI wakeup handler is unregistered before module unload
Add a synchronize_rcu() after clearing the posted interrupt wakeup handler
to ensure all readers, i.e. in-flight IRQ handlers, see the new handler
before returning to the caller. If the caller is an exiting module and
is unregistering its handler, failure to wait could result in the IRQ
handler jumping into an unloaded module.
The registration path doesn't require synchronization, as it's the
caller's responsibility to not generate interrupts it cares about until
after its handler is registered.
Fixes: 065df9c84eae ("x86/irq: Define a global vector for VT-d Posted-Interrupts") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211009001107.3936588-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM: x86: Use rw_semaphore for APICv lock to allow vCPU parallelism
Use a rw_semaphore instead of a mutex to coordinate APICv updates so that
vCPUs responding to requests can take the lock for read and run in
parallel. Using a mutex forces serialization of vCPUs even though
kvm_vcpu_update_apicv() only touches data local to that vCPU or is
protected by a different lock, e.g. SVM's ir_list_lock.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022004927.1448382-5-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM: x86: Move SVM's APICv sanity check to common x86
Move SVM's assertion that vCPU's APICv state is consistent with its VM's
state out of svm_vcpu_run() and into x86's common inner run loop. The
assertion and underlying logic is not unique to SVM, it's just that SVM
has more inhibiting conditions and thus is more likely to run headfirst
into any KVM bugs.
Add relevant comments to document exactly why the update path has unusual
ordering between the update the kick, why said ordering is safe, and also
the basic rules behind the assertion in the run loop.
Cc: Maxim Levitsky <mlevitsk@redhat.com> Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022004927.1448382-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Lukas Bulwahn [Fri, 22 Oct 2021 06:15:14 +0000 (08:15 +0200)]
riscv: do not select non-existing config ANON_INODES
Commit 38d21e5b436a ("RISC-V: Add initial skeletal KVM support") selects
the config ANON_INODES in config KVM, but the config ANON_INODES is removed
since commit bf531e279b50 ("Make anon_inodes unconditional") in 2018.
Hence, ./scripts/checkkconfigsymbols.py warns on non-existing symbols:
KVM: x86/mmu: Extract zapping of rmaps for gfn range to separate helper
Extract the zapping of rmaps, a.k.a. legacy MMU, for a gfn range to a
separate helper to clean up the unholy mess that kvm_zap_gfn_range() has
become. In addition to deep nesting, the rmaps zapping spreads out the
declaration of several variables and is generally a mess. Clean up the
mess now so that future work to improve the memslots implementation
doesn't need to deal with it.
Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022010005.1454978-4-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM: x86/mmu: Drop a redundant remote TLB flush in kvm_zap_gfn_range()
Remove an unnecessary remote TLB flush in kvm_zap_gfn_range() now that
said function holds mmu_lock for write for its entire duration. The
flush was added by the now-reverted commit to allow TDP MMU to flush while
holding mmu_lock for read, as the transition from write=>read required
dropping the lock and thus a pending flush needed to be serviced.
Fixes: 3933f64de6d6 ("Revert "KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock"") Cc: Maxim Levitsky <mlevitsk@redhat.com> Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Cc: Ben Gardon <bgardon@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022010005.1454978-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM: x86/mmu: Drop a redundant, broken remote TLB flush
A recent commit to fix the calls to kvm_flush_remote_tlbs_with_address()
in kvm_zap_gfn_range() inadvertantly added yet another flush instead of
fixing the existing flush. Drop the redundant flush, and fix the params
for the existing flush.
Cc: stable@vger.kernel.org Fixes: 55858b79f0f0 ("KVM: x86/mmu: fix parameters to kvm_flush_remote_tlbs_with_address") Cc: Maxim Levitsky <mlevitsk@redhat.com> Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com> Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022010005.1454978-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Lai Jiangshan [Tue, 19 Oct 2021 11:01:54 +0000 (19:01 +0800)]
KVM: X86: Don't unload MMU in kvm_vcpu_flush_tlb_guest()
kvm_mmu_unload() destroys all the PGD caches. Use the lighter
kvm_mmu_sync_roots() and kvm_mmu_sync_prev_roots() instead.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211019110154.4091-5-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Lai Jiangshan [Tue, 19 Oct 2021 11:01:53 +0000 (19:01 +0800)]
KVM: X86: pair smp_wmb() of mmu_try_to_unsync_pages() with smp_rmb()
The commit 819b21f56c943 ("kvm: x86: Avoid taking MMU lock
in kvm_mmu_sync_roots if no sync is needed") added smp_wmb() in
mmu_try_to_unsync_pages(), but the corresponding smp_load_acquire() isn't
used on the load of SPTE.W. smp_load_acquire() orders _subsequent_
loads after sp->is_unsync; it does not order _earlier_ loads before
the load of sp->is_unsync.
This has no functional change; smp_rmb() is a NOP on x86, and no
compiler barrier is required because there is a VMEXIT between the
load of SPTE.W and kvm_mmu_snc_roots.
Cc: Junaid Shahid <junaids@google.com> Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211019110154.4091-4-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Lai Jiangshan [Tue, 19 Oct 2021 11:01:52 +0000 (19:01 +0800)]
KVM: X86: Cache CR3 in prev_roots when PCID is disabled
The commit 6d53f75907734 ("KVM: x86: Invalidate all PGDs for the
current PCID on MOV CR3 w/ flush") invalidates all PGDs for the specific
PCID and in the case of PCID is disabled, it includes all PGDs in the
prev_roots and the commit made prev_roots totally unused in this case.
Not using prev_roots fixes a problem when CR4.PCIDE is changed 0 -> 1
before the said commit:
(CR4.PCIDE=0, CR4.PGE=1; CR3=cr3_a; the page for the guest
RIP is global; cr3_b is cached in prev_roots)
modify page tables under cr3_b
the shadow root of cr3_b is unsync in kvm
INVPCID single context
the guest expects the TLB is clean for PCID=0
change CR4.PCIDE 0 -> 1
switch to cr3_b with PCID=0,NOFLUSH=1
No sync in kvm, cr3_b is still unsync in kvm
jump to the page that was modified in step 1
shadow page tables point to the wrong page
It is a very unlikely case, but it shows that stale prev_roots can be
a problem after CR4.PCIDE changes from 0 to 1. However, to fix this
case, the commit disabled caching CR3 in prev_roots altogether when PCID
is disabled. Not all CPUs have PCID; especially the PCID support
for AMD CPUs is kind of recent. To restore the prev_roots optimization
for CR4.PCIDE=0, flush the whole MMU (including all prev_roots) when
CR4.PCIDE changes.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211019110154.4091-3-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Lai Jiangshan [Tue, 19 Oct 2021 11:01:51 +0000 (19:01 +0800)]
KVM: X86: Fix tlb flush for tdp in kvm_invalidate_pcid()
The KVM doesn't know whether any TLB for a specific pcid is cached in
the CPU when tdp is enabled. So it is better to flush all the guest
TLB when invalidating any single PCID context.
The case is very rare or even impossible since KVM generally doesn't
intercept CR3 write or INVPCID instructions when tdp is enabled, so the
fix is mostly for the sake of overall robustness.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211019110154.4091-2-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Lai Jiangshan [Sun, 19 Sep 2021 02:42:46 +0000 (10:42 +0800)]
KVM: X86: Don't reset mmu context when toggling X86_CR4_PGE
X86_CR4_PGE doesn't participate in kvm_mmu_role, so the mmu context
doesn't need to be reset. It is only required to flush all the guest
tlb.
It is also inconsistent that X86_CR4_PGE is in KVM_MMU_CR4_ROLE_BITS
while kvm_mmu_role doesn't use X86_CR4_PGE. So X86_CR4_PGE is also
removed from KVM_MMU_CR4_ROLE_BITS.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210919024246.89230-3-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Lai Jiangshan [Sun, 19 Sep 2021 02:42:45 +0000 (10:42 +0800)]
KVM: X86: Don't reset mmu context when X86_CR4_PCIDE 1->0
X86_CR4_PCIDE doesn't participate in kvm_mmu_role, so the mmu context
doesn't need to be reset. It is only required to flush all the guest
tlb.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com> Reviewed-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210919024246.89230-2-jiangshanlai@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Michael Roth [Wed, 6 Oct 2021 20:36:17 +0000 (15:36 -0500)]
KVM: selftests: set CPUID before setting sregs in vcpu creation
Recent kernels have checks to ensure the GPA values in special-purpose
registers like CR3 are within the maximum physical address range and
don't overlap with anything in the upper/reserved range. In the case of
SEV kselftest guests booting directly into 64-bit mode, CR3 needs to be
initialized to the GPA of the page table root, with the encryption bit
set. The kernel accounts for this encryption bit by removing it from
reserved bit range when the guest advertises the bit position via
KVM_SET_CPUID*, but kselftests currently call KVM_SET_SREGS as part of
vm_vcpu_add_default(), before KVM_SET_CPUID*.
As a result, KVM_SET_SREGS will return an error in these cases.
Address this by moving vcpu_set_cpuid() (which calls KVM_SET_CPUID*)
ahead of vcpu_setup() (which calls KVM_SET_SREGS).
While there, address a typo in the assertion that triggers when
KVM_SET_SREGS fails.
Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Michael Roth <michael.roth@amd.com>
Message-Id: <20211006203617.13045-1-michael.roth@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Nathan Tempelman <natet@google.com>
Wanpeng Li [Wed, 20 Oct 2021 10:13:56 +0000 (03:13 -0700)]
KVM: emulate: Comment on difference between RDPMC implementation and manual
SDM mentioned that, RDPMC:
IF (((CR4.PCE = 1) or (CPL = 0) or (CR0.PE = 0)) and (ECX indicates a supported counter))
THEN
EAX := counter[31:0];
EDX := ZeroExtend(counter[MSCB:32]);
ELSE (* ECX is not valid or CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1 *)
#GP(0);
FI;
Let's add a comment why CR0.PE isn't tested since it's impossible for CPL to be >0 if
CR0.PE=0.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1634724836-73721-1-git-send-email-wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM: x86: Add vendor name to kvm_x86_ops, use it for error messages
Paul pointed out the error messages when KVM fails to load are unhelpful
in understanding exactly what went wrong if userspace probes the "wrong"
module.
Add a mandatory kvm_x86_ops field to track vendor module names, kvm_intel
and kvm_amd, and use the name for relevant error message when KVM fails
to load so that the user knows which module failed to load.
Opportunistically tweak the "disabled by bios" error message to clarify
that _support_ was disabled, not that the module itself was magically
disabled by BIOS.
Suggested-by: Paul Menzel <pmenzel@molgen.mpg.de> Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211018183929.897461-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Junaid Shahid [Wed, 20 Oct 2021 01:06:27 +0000 (18:06 -0700)]
kvm: x86: mmu: Make NX huge page recovery period configurable
Currently, the NX huge page recovery thread wakes up every minute and
zaps 1/nx_huge_pages_recovery_ratio of the total number of split NX
huge pages at a time. This is intended to ensure that only a
relatively small number of pages get zapped at a time. But for very
large VMs (or more specifically, VMs with a large number of
executable pages), a period of 1 minute could still result in this
number being too high (unless the ratio is changed significantly,
but that can result in split pages lingering on for too long).
This change makes the period configurable instead of fixing it at
1 minute. Users of large VMs can then adjust the period and/or the
ratio to reduce the number of pages zapped at one time while still
maintaining the same overall duration for cycling through the
entire list. By default, KVM derives a period from the ratio such
that a page will remain on the list for 1 hour on average.
Signed-off-by: Junaid Shahid <junaids@google.com>
Message-Id: <20211020010627.305925-1-junaids@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Wanpeng Li [Tue, 19 Oct 2021 08:12:39 +0000 (01:12 -0700)]
KVM: vPMU: Fill get_msr MSR_CORE_PERF_GLOBAL_OVF_CTRL w/ 0
SDM section 18.2.3 mentioned that:
"IA32_PERF_GLOBAL_OVF_CTL MSR allows software to clear overflow indicator(s) of
any general-purpose or fixed-function counters via a single WRMSR."
It is R/W mentioned by SDM, we read this msr on bare-metal during perf testing,
the value is always 0 for ICX/SKX boxes on hands. Let's fill get_msr
MSR_CORE_PERF_GLOBAL_OVF_CTRL w/ 0 as hardware behavior and drop
global_ovf_ctrl variable.
Tested-by: Like Xu <likexu@tencent.com> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1634631160-67276-2-git-send-email-wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
David Matlack [Tue, 19 Oct 2021 16:22:23 +0000 (16:22 +0000)]
KVM: x86/mmu: Rename slot_handle_leaf to slot_handle_level_4k
slot_handle_leaf is a misnomer because it only operates on 4K SPTEs
whereas "leaf" is used to describe any valid terminal SPTE (4K or
large page). Rename slot_handle_leaf to slot_handle_level_4k to
avoid confusion.
Making this change makes it more obvious there is a benign discrepency
between the legacy MMU and the TDP MMU when it comes to dirty logging.
The legacy MMU only iterates through 4K SPTEs when zapping for
collapsing and when clearing D-bits. The TDP MMU, on the other hand,
iterates through SPTEs on all levels.
The TDP MMU behavior of zapping SPTEs at all levels is technically
overkill for its current dirty logging implementation, which always
demotes to 4k SPTES, but both the TDP MMU and legacy MMU zap if and only
if the SPTE can be replaced by a larger page, i.e. will not spuriously
zap 2m (or larger) SPTEs. Opportunistically add comments to explain this
discrepency in the code.
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20211019162223.3935109-1-dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Xiaoyao Li [Fri, 27 Aug 2021 07:02:46 +0000 (15:02 +0800)]
KVM: VMX: RTIT_CTL_BRANCH_EN has no dependency on other CPUID bit
Per Intel SDM, RTIT_CTL_BRANCH_EN bit has no dependency on any CPUID
leaf 0x14.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20210827070249.924633-5-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Xiaoyao Li [Fri, 27 Aug 2021 07:02:45 +0000 (15:02 +0800)]
KVM: VMX: Rename pt_desc.addr_range to pt_desc.num_address_ranges
To better self explain the meaning of this field and match the
PT_CAP_num_address_ranges constatn.
Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20210827070249.924633-4-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Xiaoyao Li [Fri, 27 Aug 2021 07:02:44 +0000 (15:02 +0800)]
KVM: VMX: Use precomputed vmx->pt_desc.addr_range
The number of valid PT ADDR MSRs for the guest is precomputed in
vmx->pt_desc.addr_range. Use it instead of calculating again.
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20210827070249.924633-3-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Xiaoyao Li [Fri, 27 Aug 2021 07:02:43 +0000 (15:02 +0800)]
KVM: VMX: Restore host's MSR_IA32_RTIT_CTL when it's not zero
A minor optimization to WRMSR MSR_IA32_RTIT_CTL when necessary.
Opportunistically refine the comment to call out that KVM requires
VM_EXIT_CLEAR_IA32_RTIT_CTL to expose PT to the guest.
Reviewed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-Id: <20210827070249.924633-2-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Wed, 29 Sep 2021 13:19:32 +0000 (09:19 -0400)]
KVM: x86/mmu: clean up prefetch/prefault/speculative naming
"prefetch", "prefault" and "speculative" are used throughout KVM to mean
the same thing. Use a single name, standardizing on "prefetch" which
is already used by various functions such as direct_pte_prefetch,
FNAME(prefetch_gpte), FNAME(pte_prefetch), etc.
Suggested-by: David Matlack <dmatlack@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
David Stevens [Fri, 15 Oct 2021 16:30:21 +0000 (12:30 -0400)]
KVM: cleanup allocation of rmaps and page tracking data
Unify the flags for rmaps and page tracking data, using a
single flag in struct kvm_arch and a single loop to go
over all the address spaces and memslots. This avoids
code duplication between alloc_all_memslots_rmaps and
kvm_page_track_enable_mmu_write_tracking.
Signed-off-by: David Stevens <stevensd@chromium.org>
[This patch is the delta between David's v2 and v3, with conflicts
fixed and my own commit message. - Paolo] Co-developed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Marc Zyngier [Thu, 21 Oct 2021 10:40:03 +0000 (11:40 +0100)]
Merge branch kvm/selftests/memslot into kvmarm-master/next
* kvm/selftests/memslot:
: .
: Enable KVM memslot selftests on arm64, making them less
: x86 specific.
: .
KVM: selftests: Build the memslot tests for arm64
KVM: selftests: Make memslot_perf_test arch independent
KVM: selftests: Make memslot_perf_test arch independent
memslot_perf_test uses ucalls for synchronization between guest and
host. Ucalls API is architecture independent: tests do not need to know
details like what kind of exit they generate on a specific arch. More
specifically, there is no need to check whether an exit is KVM_EXIT_IO
in x86 for the host to know that the exit is ucall related, as
get_ucall() already makes that check.
Change memslot_perf_test to not require specifying what exit does a
ucall generate. Also add a missing ucall_init.
Halil Pasic [Tue, 19 Oct 2021 17:54:00 +0000 (19:54 +0200)]
KVM: s390: preserve deliverable_mask in __airqs_kick_single_vcpu
Changing the deliverable mask in __airqs_kick_single_vcpu() is a bug. If
one idle vcpu can't take the interrupts we want to deliver, we should
look for another vcpu that can, instead of saying that we don't want
to deliver these interrupts by clearing the bits from the
deliverable_mask.
Fixes: a2ab0f7e961a ("KVM: s390: add gib_alert_irq_handler()") Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Michael Mueller <mimu@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Link: https://lore.kernel.org/r/20211019175401.3757927-3-pasic@linux.ibm.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Halil Pasic [Tue, 19 Oct 2021 17:53:59 +0000 (19:53 +0200)]
KVM: s390: clear kicked_mask before sleeping again
The idea behind kicked mask is that we should not re-kick a vcpu that
is already in the "kick" process, i.e. that was kicked and is
is about to be dispatched if certain conditions are met.
The problem with the current implementation is, that it assumes the
kicked vcpu is going to enter SIE shortly. But under certain
circumstances, the vcpu we just kicked will be deemed non-runnable and
will remain in wait state. This can happen, if the interrupt(s) this
vcpu got kicked to deal with got already cleared (because the interrupts
got delivered to another vcpu). In this case kvm_arch_vcpu_runnable()
would return false, and the vcpu would remain in kvm_vcpu_block(),
but this time with its kicked_mask bit set. So next time around we
wouldn't kick the vcpu form __airqs_kick_single_vcpu(), but would assume
that we just kicked it.
Let us make sure the kicked_mask is cleared before we give up on
re-dispatching the vcpu.
Fixes: a2ab0f7e961a ("KVM: s390: add gib_alert_irq_handler()") Reported-by: Matthew Rosato <mjrosato@linux.ibm.com> Signed-off-by: Halil Pasic <pasic@linux.ibm.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Michael Mueller <mimu@linux.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Link: https://lore.kernel.org/r/20211019175401.3757927-2-pasic@linux.ibm.com Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Oliver Upton [Thu, 16 Sep 2021 18:15:51 +0000 (18:15 +0000)]
selftests: KVM: Introduce system counter offset test
Introduce a KVM selftest to verify that userspace manipulation of the
TSC (via the new vCPU attribute) results in the correct behavior within
the guest.
Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-6-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Thu, 16 Sep 2021 18:15:50 +0000 (18:15 +0000)]
selftests: KVM: Add helpers for vCPU device attributes
vCPU file descriptors are abstracted away from test code in KVM
selftests, meaning that tests cannot directly access a vCPU's device
attributes. Add helpers that tests can use to get at vCPU device
attributes.
Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-5-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The KVM_CREATE_DEVICE and KVM_{GET,SET}_DEVICE_ATTR ioctls are defined
to return a value of zero on success. As such, tighten the assertions in
the helper functions to only pass if the return code is zero.
Suggested-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-4-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Thu, 16 Sep 2021 18:15:48 +0000 (18:15 +0000)]
selftests: KVM: Add test for KVM_{GET,SET}_CLOCK
Add a selftest for the new KVM clock UAPI that was introduced. Ensure
that the KVM clock is consistent between userspace and the guest, and
that the difference in realtime will only ever cause the KVM clock to
advance forward.
Cc: Andrew Jones <drjones@redhat.com> Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-3-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Thu, 16 Sep 2021 18:15:47 +0000 (18:15 +0000)]
tools: arch: x86: pull in pvclock headers
Copy over approximately clean versions of the pvclock headers into
tools. Reconcile headers/symbols missing in tools that are unneeded.
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20210916181555.973085-2-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Thu, 16 Sep 2021 18:15:38 +0000 (18:15 +0000)]
KVM: x86: Expose TSC offset controls to userspace
To date, VMM-directed TSC synchronization and migration has been a bit
messy. KVM has some baked-in heuristics around TSC writes to infer if
the VMM is attempting to synchronize. This is problematic, as it depends
on host userspace writing to the guest's TSC within 1 second of the last
write.
A much cleaner approach to configuring the guest's views of the TSC is to
simply migrate the TSC offset for every vCPU. Offsets are idempotent,
and thus not subject to change depending on when the VMM actually
reads/writes values from/to KVM. The VMM can then read the TSC once with
KVM_GET_CLOCK to capture a (realtime, host_tsc) pair at the instant when
the guest is paused.
Cc: David Matlack <dmatlack@google.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210916181538.968978-8-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Thu, 16 Sep 2021 18:15:37 +0000 (18:15 +0000)]
KVM: x86: Refactor tsc synchronization code
Refactor kvm_synchronize_tsc to make a new function that allows callers
to specify TSC parameters (offset, value, nanoseconds, etc.) explicitly
for the sake of participating in TSC synchronization.
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20210916181538.968978-7-oupton@google.com>
[Make sure kvm->arch.cur_tsc_generation and vcpu->arch.this_tsc_generation are
equal at the end of __kvm_synchronize_tsc, if matched is false. Reported by
Maxim Levitsky. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Thu, 16 Sep 2021 18:15:36 +0000 (18:15 +0000)]
kvm: x86: protect masterclock with a seqcount
Protect the reference point for kvmclock with a seqcount, so that
kvmclock updates for all vCPUs can proceed in parallel. Xen runstate
updates will also run in parallel and not bounce the kvmclock cacheline.
Of the variables that were protected by pvclock_gtod_sync_lock,
nr_vcpus_matched_tsc is different because it is updated outside
pvclock_update_vm_gtod_copy and read inside it. Therefore, we
need to keep it protected by a spinlock. In fact it must now
be a raw spinlock, because pvclock_update_vm_gtod_copy, being the
write-side of a seqcount, is non-preemptible. Since we already
have tsc_write_lock which is a raw spinlock, we can just use
tsc_write_lock as the lock that protects the write-side of the
seqcount.
Co-developed-by: Oliver Upton <oupton@google.com>
Message-Id: <20210916181538.968978-6-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Thu, 16 Sep 2021 18:15:35 +0000 (18:15 +0000)]
KVM: x86: Report host tsc and realtime values in KVM_GET_CLOCK
Handling the migration of TSCs correctly is difficult, in part because
Linux does not provide userspace with the ability to retrieve a (TSC,
realtime) clock pair for a single instant in time. In lieu of a more
convenient facility, KVM can report similar information in the kvm_clock
structure.
Provide userspace with a host TSC & realtime pair iff the realtime clock
is based on the TSC. If userspace provides KVM_SET_CLOCK with a valid
realtime value, advance the KVM clock by the amount of elapsed time. Do
not step the KVM clock backwards, though, as it is a monotonic
oscillator.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Oliver Upton <oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210916181538.968978-5-oupton@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Fri, 15 Oct 2021 08:50:01 +0000 (04:50 -0400)]
KVM: x86: avoid warning with -Wbitwise-instead-of-logical
This is a new warning in clang top-of-tree (will be clang 14):
In file included from arch/x86/kvm/mmu/mmu.c:27:
arch/x86/kvm/mmu/spte.h:318:9: error: use of bitwise '|' with boolean operands [-Werror,-Wbitwise-instead-of-logical]
return __is_bad_mt_xwr(rsvd_check, spte) |
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
||
arch/x86/kvm/mmu/spte.h:318:9: note: cast one or both operands to int to silence this warning
The code is fine, but change it anyway to shut up this clever clogs
of a compiler.
Reported-by: torvic9@mailbox.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Fri, 15 Oct 2021 17:05:00 +0000 (13:05 -0400)]
KVM: X86: fix lazy allocation of rmaps
If allocation of rmaps fails, but some of the pointers have already been written,
those pointers can be cleaned up when the memslot is freed, or even reused later
for another attempt at allocating the rmaps. Therefore there is no need to
WARN, as done for example in memslot_rmap_alloc, but the allocation *must* be
skipped lest KVM will overwrite the previous pointer and will indeed leak memory.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Marc Zyngier [Mon, 18 Oct 2021 16:20:50 +0000 (17:20 +0100)]
Merge branch kvm-arm64/pkvm/fixed-features into kvmarm-master/next
* kvm-arm64/pkvm/fixed-features: (22 commits)
: .
: Add the pKVM fixed feature that allows a bunch of exceptions
: to either be forbidden or be easily handled at EL2.
: .
KVM: arm64: pkvm: Give priority to standard traps over pvm handling
KVM: arm64: pkvm: Pass vpcu instead of kvm to kvm_get_exit_handler_array()
KVM: arm64: pkvm: Move kvm_handle_pvm_restricted around
KVM: arm64: pkvm: Consolidate include files
KVM: arm64: pkvm: Preserve pending SError on exit from AArch32
KVM: arm64: pkvm: Handle GICv3 traps as required
KVM: arm64: pkvm: Drop sysregs that should never be routed to the host
KVM: arm64: pkvm: Drop AArch32-specific registers
KVM: arm64: pkvm: Make the ERR/ERX*_EL1 registers RAZ/WI
KVM: arm64: pkvm: Use a single function to expose all id-regs
KVM: arm64: Fix early exit ptrauth handling
KVM: arm64: Handle protected guests at 32 bits
KVM: arm64: Trap access to pVM restricted features
KVM: arm64: Move sanitized copies of CPU features
KVM: arm64: Initialize trap registers for protected VMs
KVM: arm64: Add handlers for protected VM System Registers
KVM: arm64: Simplify masking out MTE in feature id reg
KVM: arm64: Add missing field descriptor for MDCR_EL2
KVM: arm64: Pass struct kvm to per-EC handlers
KVM: arm64: Move early handlers to per-EC handlers
...
Marc Zyngier [Wed, 13 Oct 2021 12:03:45 +0000 (13:03 +0100)]
KVM: arm64: pkvm: Pass vpcu instead of kvm to kvm_get_exit_handler_array()
Passing a VM pointer around is odd, and results in extra work on
VHE. Follow the rest of the design that uses the vcpu instead, and
let the nVHE code look into the struct kvm as required.
Marc Zyngier [Wed, 13 Oct 2021 12:03:37 +0000 (13:03 +0100)]
KVM: arm64: pkvm: Use a single function to expose all id-regs
Rather than exposing a whole set of helper functions to retrieve
individual ID registers, use the existing decoding tree and expose
a single helper instead.
This allow a number of functions to be made static, and we now
have a single entry point to maintain.
Marc Zyngier [Wed, 13 Oct 2021 12:03:36 +0000 (13:03 +0100)]
KVM: arm64: Fix early exit ptrauth handling
The previous rework of the early exit code to provide an EC-based
decoding tree missed the fact that we have two trap paths for
ptrauth: the instructions (EC_PAC) and the sysregs (EC_SYS64).
Rework the handlers to call the ptrauth handling code on both
paths.
Marc Zyngier [Sun, 17 Oct 2021 10:29:36 +0000 (11:29 +0100)]
Merge branch kvm-arm64/memory-accounting into kvmarm-master/next
* kvm-arm64/memory-accounting:
: .
: Sprinkle a bunch of GFP_KERNEL_ACCOUNT all over the code base
: to better track memory allocation made on behalf of a VM.
: .
KVM: arm64: Add memcg accounting to KVM allocations
KVM: arm64: vgic: Add memcg accounting to vgic allocations
Jia He [Tue, 7 Sep 2021 12:31:12 +0000 (20:31 +0800)]
KVM: arm64: Add memcg accounting to KVM allocations
Inspired by commit c6c49ac70d50 ("kvm: x86: Add memcg accounting to KVM
allocations"), it would be better to make arm64 KVM consistent with
common kvm codes.
The memory allocations of VM scope should be charged into VM process
cgroup, hence change GFP_KERNEL to GFP_KERNEL_ACCOUNT.
There remain a few cases since these allocations are global, not in VM
scope.
Jia He [Tue, 7 Sep 2021 12:31:11 +0000 (20:31 +0800)]
KVM: arm64: vgic: Add memcg accounting to vgic allocations
Inspired by commit c6c49ac70d50 ("kvm: x86: Add memcg accounting to KVM
allocations"), it would be better to make arm64 vgic consistent with
common kvm codes.
The memory allocations of VM scope should be charged into VM process
cgroup, hence change GFP_KERNEL to GFP_KERNEL_ACCOUNT.
There remain a few cases since these allocations are global, not in VM
scope.
Marc Zyngier [Sun, 17 Oct 2021 10:19:42 +0000 (11:19 +0100)]
Merge branch kvm-arm64/selftest/timer into kvmarm-master/next
* kvm-arm64/selftest/timer:
: .
: Add a set of selftests for the KVM/arm64 timer emulation.
: Comes with a minimal GICv3 infrastructure.
: .
KVM: arm64: selftests: arch_timer: Support vCPU migration
KVM: arm64: selftests: Add arch_timer test
KVM: arm64: selftests: Add host support for vGIC
KVM: arm64: selftests: Add basic GICv3 support
KVM: arm64: selftests: Add light-weight spinlock support
KVM: arm64: selftests: Add guest support to get the vcpuid
KVM: arm64: selftests: Maintain consistency for vcpuid type
KVM: arm64: selftests: Add support to disable and enable local IRQs
KVM: arm64: selftests: Add basic support to generate delays
KVM: arm64: selftests: Add basic support for arch_timers
KVM: arm64: selftests: Add support for cpu_relax
KVM: arm64: selftests: Introduce ARM64_SYS_KVM_REG
tools: arm64: Import sysreg.h
KVM: arm64: selftests: Add MMIO readl/writel support
KVM: arm64: selftests: arch_timer: Support vCPU migration
Since the timer stack (hardware and KVM) is per-CPU, there
are potential chances for races to occur when the scheduler
decides to migrate a vCPU thread to a different physical CPU.
Hence, include an option to stress-test this part as well by
forcing the vCPUs to migrate across physical CPUs in the
system at a particular rate.
Originally, the bug for the fix with commit 7879cf088716791
("KVM: arm64: vgic: Resample HW pending state on deactivation")
was discovered using arch_timer test with vCPU migrations and
can be easily reproduced.
Add a KVM selftest to validate the arch_timer functionality.
Primarily, the test sets up periodic timer interrupts and
validates the basic architectural expectations upon its receipt.
The test provides command-line options to configure the period
of the timer, number of iterations, and number of vCPUs.
Implement a simple library to perform vGIC-v3 setup
from a host point of view. This includes creating a
vGIC device, setting up distributor and redistributor
attributes, and mapping the guest physical addresses.
The definition of REDIST_REGION_ATTR_ADDR is taken from
aarch64/vgic_init test. Hence, replace the definition
by including vgic.h in the test file.
KVM: arm64: selftests: Add guest support to get the vcpuid
At times, such as when in the interrupt handler, the guest wants
to get the vcpuid that it's running on to pull the per-cpu private
data. As a result, introduce guest_get_vcpuid() that returns the
vcpuid of the calling vcpu. The interface is architecture
independent, but defined only for arm64 as of now.
Suggested-by: Reiji Watanabe <reijiw@google.com> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com> Reviewed-by: Ricardo Koller <ricarkol@google.com> Reviewed-by: Reiji Watanabe <reijiw@google.com> Reviewed-by: Andrew Jones <drjones@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20211007233439.1826892-11-rananta@google.com
KVM: arm64: selftests: Maintain consistency for vcpuid type
The prototype of aarch64_vcpu_setup() accepts vcpuid as
'int', while the rest of the aarch64 (and struct vcpu)
carries it as 'uint32_t'. Hence, change the prototype
to make it consistent throughout the board.
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