From 01801e41fab92ce41efcb88e02bbc35649b6ab2f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 20 Sep 2021 17:03:01 -0700 Subject: [PATCH] KVM: VMX: Move RESET emulation to vmx_vcpu_reset() Move vCPU RESET emulation, including initializating of select VMCS state, to vmx_vcpu_reset(). Drop the open coded "vCPU load" sequence, as ->vcpu_reset() is invoked while the vCPU is properly loaded (which is kind of the point of ->vcpu_reset()...). Hopefully KVM will someday expose a dedicated RESET ioctl(), and in the meantime separating "create" from "RESET" is a nice cleanup. Deferring VMCS initialization is effectively a nop as it's impossible to safely access the VMCS between the current call site and its new home, as both the vCPU and the pCPU are put immediately after init_vmcs(), i.e. the VMCS isn't guaranteed to be loaded. Note, task preemption is not a problem as vmx_sched_in() _can't_ touch the VMCS as ->sched_in() is invoked before the vCPU, and thus VMCS, is reloaded. I.e. the preemption path also can't consume VMCS state. Cc: Reiji Watanabe Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini Message-Id: <20210921000303.400537-9-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/vmx.c | 63 +++++++++++++++++++++--------------------- 1 file changed, 32 insertions(+), 31 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 65be361669893..b8bfb46d58f47 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4328,10 +4328,6 @@ static u32 vmx_secondary_exec_control(struct vcpu_vmx *vmx) #define VMX_XSS_EXIT_BITMAP 0 -/* - * Noting that the initialization of Guest-state Area of VMCS is in - * vmx_vcpu_reset(). - */ static void init_vmcs(struct vcpu_vmx *vmx) { if (nested) @@ -4436,10 +4432,40 @@ static void init_vmcs(struct vcpu_vmx *vmx) vmx_setup_uret_msrs(vmx); } +static void __vmx_vcpu_reset(struct kvm_vcpu *vcpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + + init_vmcs(vmx); + + if (nested) + memcpy(&vmx->nested.msrs, &vmcs_config.nested, sizeof(vmx->nested.msrs)); + + vcpu_setup_sgx_lepubkeyhash(vcpu); + + vmx->nested.posted_intr_nv = -1; + vmx->nested.vmxon_ptr = INVALID_GPA; + vmx->nested.current_vmptr = INVALID_GPA; + vmx->nested.hv_evmcs_vmptr = EVMPTR_INVALID; + + vcpu->arch.microcode_version = 0x100000000ULL; + vmx->msr_ia32_feature_control_valid_bits = FEAT_CTL_LOCKED; + + /* + * Enforce invariant: pi_desc.nv is always either POSTED_INTR_VECTOR + * or POSTED_INTR_WAKEUP_VECTOR. + */ + vmx->pi_desc.nv = POSTED_INTR_VECTOR; + vmx->pi_desc.sn = 1; +} + static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) { struct vcpu_vmx *vmx = to_vmx(vcpu); + if (!init_event) + __vmx_vcpu_reset(vcpu); + vmx->rmode.vm86_active = 0; vmx->spec_ctrl = 0; @@ -6816,7 +6842,7 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu) { struct vmx_uret_msr *tsx_ctrl; struct vcpu_vmx *vmx; - int i, cpu, err; + int i, err; BUILD_BUG_ON(offsetof(struct vcpu_vmx, vcpu) != 0); vmx = to_vmx(vcpu); @@ -6875,12 +6901,7 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu) } vmx->loaded_vmcs = &vmx->vmcs01; - cpu = get_cpu(); - vmx_vcpu_load(vcpu, cpu); - vcpu->cpu = cpu; - init_vmcs(vmx); - vmx_vcpu_put(vcpu); - put_cpu(); + if (cpu_need_virtualize_apic_accesses(vcpu)) { err = alloc_apic_access_page(vcpu->kvm); if (err) @@ -6893,26 +6914,6 @@ static int vmx_create_vcpu(struct kvm_vcpu *vcpu) goto free_vmcs; } - if (nested) - memcpy(&vmx->nested.msrs, &vmcs_config.nested, sizeof(vmx->nested.msrs)); - - vcpu_setup_sgx_lepubkeyhash(vcpu); - - vmx->nested.posted_intr_nv = -1; - vmx->nested.vmxon_ptr = INVALID_GPA; - vmx->nested.current_vmptr = INVALID_GPA; - vmx->nested.hv_evmcs_vmptr = EVMPTR_INVALID; - - vcpu->arch.microcode_version = 0x100000000ULL; - vmx->msr_ia32_feature_control_valid_bits = FEAT_CTL_LOCKED; - - /* - * Enforce invariant: pi_desc.nv is always either POSTED_INTR_VECTOR - * or POSTED_INTR_WAKEUP_VECTOR. - */ - vmx->pi_desc.nv = POSTED_INTR_VECTOR; - vmx->pi_desc.sn = 1; - return 0; free_vmcs: -- 2.39.5