RISC-V: Add initial skeletal KVM support

This patch adds initial skeletal KVM RISC-V support which has:
1. A simple implementation of arch specific VM functions
   except kvm_vm_ioctl_get_dirty_log() which will implemeted
   in-future as part of stage2 page loging.
2. Stubs of required arch specific VCPU functions except
   kvm_arch_vcpu_ioctl_run() which is semi-complete and
   extended by subsequent patches.
3. Stubs for required arch specific stage2 MMU functions.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 301a54233c7e26a598eb63f4a75aad9301c12141..f5fe8a7f0e244331ddc98c67e745c8a9db2c82f2 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -562,4 +562,5 @@ source "kernel/power/Kconfig"
 
 endmenu
 
+source "arch/riscv/kvm/Kconfig"
 source "drivers/firmware/Kconfig"

diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 0eb4568fbd290c79e121a5c6f0f803c9fc8597df..58c1a28e20bb4a459a4535dc518fbefc21c30c30 100644 (file)
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -100,6 +100,7 @@ endif
 head-y := arch/riscv/kernel/head.o
 
 core-$(CONFIG_RISCV_ERRATA_ALTERNATIVE) += arch/riscv/errata/
+core-$(CONFIG_KVM) += arch/riscv/kvm/
 
 libs-y += arch/riscv/lib/
 libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h
new file mode 100644 (file)
index 0000000..08a8f53
--- /dev/null
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -0,0 +1,84 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#ifndef __RISCV_KVM_HOST_H__
+#define __RISCV_KVM_HOST_H__
+
+#include <linux/types.h>
+#include <linux/kvm.h>
+#include <linux/kvm_types.h>
+
+#ifdef CONFIG_64BIT
+#define KVM_MAX_VCPUS                  (1U << 16)
+#else
+#define KVM_MAX_VCPUS                  (1U << 9)
+#endif
+
+#define KVM_HALT_POLL_NS_DEFAULT       500000
+
+#define KVM_VCPU_MAX_FEATURES          0
+
+#define KVM_REQ_SLEEP \
+       KVM_ARCH_REQ_FLAGS(0, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
+#define KVM_REQ_VCPU_RESET             KVM_ARCH_REQ(1)
+
+struct kvm_vm_stat {
+       struct kvm_vm_stat_generic generic;
+};
+
+struct kvm_vcpu_stat {
+       struct kvm_vcpu_stat_generic generic;
+       u64 ecall_exit_stat;
+       u64 wfi_exit_stat;
+       u64 mmio_exit_user;
+       u64 mmio_exit_kernel;
+       u64 exits;
+};
+
+struct kvm_arch_memory_slot {
+};
+
+struct kvm_arch {
+       /* stage2 page table */
+       pgd_t *pgd;
+       phys_addr_t pgd_phys;
+};
+
+struct kvm_cpu_trap {
+       unsigned long sepc;
+       unsigned long scause;
+       unsigned long stval;
+       unsigned long htval;
+       unsigned long htinst;
+};
+
+struct kvm_vcpu_arch {
+       /* Don't run the VCPU (blocked) */
+       bool pause;
+
+       /* SRCU lock index for in-kernel run loop */
+       int srcu_idx;
+};
+
+static inline void kvm_arch_hardware_unsetup(void) {}
+static inline void kvm_arch_sync_events(struct kvm *kvm) {}
+static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {}
+static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {}
+
+void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu);
+int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm);
+void kvm_riscv_stage2_free_pgd(struct kvm *kvm);
+void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu);
+
+int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run);
+int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
+                       struct kvm_cpu_trap *trap);
+
+static inline void __kvm_riscv_switch_to(struct kvm_vcpu_arch *vcpu_arch) {}
+
+#endif /* __RISCV_KVM_HOST_H__ */

diff --git a/arch/riscv/include/asm/kvm_types.h b/arch/riscv/include/asm/kvm_types.h
new file mode 100644 (file)
index 0000000..e476b40
--- /dev/null
+++ b/arch/riscv/include/asm/kvm_types.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_RISCV_KVM_TYPES_H
+#define _ASM_RISCV_KVM_TYPES_H
+
+#define KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE 40
+
+#endif /* _ASM_RISCV_KVM_TYPES_H */

diff --git a/arch/riscv/include/uapi/asm/kvm.h b/arch/riscv/include/uapi/asm/kvm.h
new file mode 100644 (file)
index 0000000..984d041
--- /dev/null
+++ b/arch/riscv/include/uapi/asm/kvm.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#ifndef __LINUX_KVM_RISCV_H
+#define __LINUX_KVM_RISCV_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+#include <asm/ptrace.h>
+
+#define __KVM_HAVE_READONLY_MEM
+
+#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
+
+/* for KVM_GET_REGS and KVM_SET_REGS */
+struct kvm_regs {
+};
+
+/* for KVM_GET_FPU and KVM_SET_FPU */
+struct kvm_fpu {
+};
+
+/* KVM Debug exit structure */
+struct kvm_debug_exit_arch {
+};
+
+/* for KVM_SET_GUEST_DEBUG */
+struct kvm_guest_debug_arch {
+};
+
+/* definition of registers in kvm_run */
+struct kvm_sync_regs {
+};
+
+/* dummy definition */
+struct kvm_sregs {
+};
+
+#endif
+
+#endif /* __LINUX_KVM_RISCV_H */

diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig
new file mode 100644 (file)
index 0000000..88edd47
--- /dev/null
+++ b/arch/riscv/kvm/Kconfig
@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# KVM configuration
+#
+
+source "virt/kvm/Kconfig"
+
+menuconfig VIRTUALIZATION
+       bool "Virtualization"
+       help
+         Say Y here to get to see options for using your Linux host to run
+         other operating systems inside virtual machines (guests).
+         This option alone does not add any kernel code.
+
+         If you say N, all options in this submenu will be skipped and
+         disabled.
+
+if VIRTUALIZATION
+
+config KVM
+       tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)"
+       depends on RISCV_SBI && MMU
+       select PREEMPT_NOTIFIERS
+       select ANON_INODES
+       select KVM_MMIO
+       select HAVE_KVM_VCPU_ASYNC_IOCTL
+       select SRCU
+       help
+         Support hosting virtualized guest machines.
+
+         If unsure, say N.
+
+endif # VIRTUALIZATION

diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
new file mode 100644 (file)
index 0000000..4732094
--- /dev/null
+++ b/arch/riscv/kvm/Makefile
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for RISC-V KVM support
+#
+
+ccflags-y += -I $(srctree)/$(src)
+
+KVM := ../../../virt/kvm
+
+obj-$(CONFIG_KVM) += kvm.o
+
+kvm-y += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/binary_stats.o \
+        main.o vm.o mmu.o vcpu.o vcpu_exit.o

diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c
new file mode 100644 (file)
index 0000000..47926f0
--- /dev/null
+++ b/arch/riscv/kvm/main.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/kvm_host.h>
+#include <asm/csr.h>
+#include <asm/hwcap.h>
+#include <asm/sbi.h>
+
+long kvm_arch_dev_ioctl(struct file *filp,
+                       unsigned int ioctl, unsigned long arg)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_check_processor_compat(void *opaque)
+{
+       return 0;
+}
+
+int kvm_arch_hardware_setup(void *opaque)
+{
+       return 0;
+}
+
+int kvm_arch_hardware_enable(void)
+{
+       unsigned long hideleg, hedeleg;
+
+       hedeleg = 0;
+       hedeleg |= (1UL << EXC_INST_MISALIGNED);
+       hedeleg |= (1UL << EXC_BREAKPOINT);
+       hedeleg |= (1UL << EXC_SYSCALL);
+       hedeleg |= (1UL << EXC_INST_PAGE_FAULT);
+       hedeleg |= (1UL << EXC_LOAD_PAGE_FAULT);
+       hedeleg |= (1UL << EXC_STORE_PAGE_FAULT);
+       csr_write(CSR_HEDELEG, hedeleg);
+
+       hideleg = 0;
+       hideleg |= (1UL << IRQ_VS_SOFT);
+       hideleg |= (1UL << IRQ_VS_TIMER);
+       hideleg |= (1UL << IRQ_VS_EXT);
+       csr_write(CSR_HIDELEG, hideleg);
+
+       csr_write(CSR_HCOUNTEREN, -1UL);
+
+       csr_write(CSR_HVIP, 0);
+
+       return 0;
+}
+
+void kvm_arch_hardware_disable(void)
+{
+       csr_write(CSR_HEDELEG, 0);
+       csr_write(CSR_HIDELEG, 0);
+}
+
+int kvm_arch_init(void *opaque)
+{
+       if (!riscv_isa_extension_available(NULL, h)) {
+               kvm_info("hypervisor extension not available\n");
+               return -ENODEV;
+       }
+
+       if (sbi_spec_is_0_1()) {
+               kvm_info("require SBI v0.2 or higher\n");
+               return -ENODEV;
+       }
+
+       if (sbi_probe_extension(SBI_EXT_RFENCE) <= 0) {
+               kvm_info("require SBI RFENCE extension\n");
+               return -ENODEV;
+       }
+
+       kvm_info("hypervisor extension available\n");
+
+       return 0;
+}
+
+void kvm_arch_exit(void)
+{
+}
+
+static int riscv_kvm_init(void)
+{
+       return kvm_init(NULL, sizeof(struct kvm_vcpu), 0, THIS_MODULE);
+}
+module_init(riscv_kvm_init);

diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c
new file mode 100644 (file)
index 0000000..abfd2b2
--- /dev/null
+++ b/arch/riscv/kvm/mmu.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/hugetlb.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/kvm_host.h>
+#include <linux/sched/signal.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+void kvm_arch_sync_dirty_log(struct kvm *kvm, struct kvm_memory_slot *memslot)
+{
+}
+
+void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free)
+{
+}
+
+void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
+{
+}
+
+void kvm_arch_flush_shadow_all(struct kvm *kvm)
+{
+       /* TODO: */
+}
+
+void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
+                                  struct kvm_memory_slot *slot)
+{
+}
+
+void kvm_arch_commit_memory_region(struct kvm *kvm,
+                               const struct kvm_userspace_memory_region *mem,
+                               struct kvm_memory_slot *old,
+                               const struct kvm_memory_slot *new,
+                               enum kvm_mr_change change)
+{
+       /* TODO: */
+}
+
+int kvm_arch_prepare_memory_region(struct kvm *kvm,
+                               struct kvm_memory_slot *memslot,
+                               const struct kvm_userspace_memory_region *mem,
+                               enum kvm_mr_change change)
+{
+       /* TODO: */
+       return 0;
+}
+
+void kvm_riscv_stage2_flush_cache(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+}
+
+int kvm_riscv_stage2_alloc_pgd(struct kvm *kvm)
+{
+       /* TODO: */
+       return 0;
+}
+
+void kvm_riscv_stage2_free_pgd(struct kvm *kvm)
+{
+       /* TODO: */
+}
+
+void kvm_riscv_stage2_update_hgatp(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+}

diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c
new file mode 100644 (file)
index 0000000..810b7ef
--- /dev/null
+++ b/arch/riscv/kvm/vcpu.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kdebug.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/sched/signal.h>
+#include <linux/fs.h>
+#include <linux/kvm_host.h>
+#include <asm/csr.h>
+#include <asm/delay.h>
+#include <asm/hwcap.h>
+
+const struct _kvm_stats_desc kvm_vcpu_stats_desc[] = {
+       KVM_GENERIC_VCPU_STATS(),
+       STATS_DESC_COUNTER(VCPU, ecall_exit_stat),
+       STATS_DESC_COUNTER(VCPU, wfi_exit_stat),
+       STATS_DESC_COUNTER(VCPU, mmio_exit_user),
+       STATS_DESC_COUNTER(VCPU, mmio_exit_kernel),
+       STATS_DESC_COUNTER(VCPU, exits)
+};
+
+const struct kvm_stats_header kvm_vcpu_stats_header = {
+       .name_size = KVM_STATS_NAME_SIZE,
+       .num_desc = ARRAY_SIZE(kvm_vcpu_stats_desc),
+       .id_offset = sizeof(struct kvm_stats_header),
+       .desc_offset = sizeof(struct kvm_stats_header) + KVM_STATS_NAME_SIZE,
+       .data_offset = sizeof(struct kvm_stats_header) + KVM_STATS_NAME_SIZE +
+                      sizeof(kvm_vcpu_stats_desc),
+};
+
+int kvm_arch_vcpu_precreate(struct kvm *kvm, unsigned int id)
+{
+       return 0;
+}
+
+int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+       return 0;
+}
+
+void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
+{
+}
+
+int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+       return 0;
+}
+
+void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+}
+
+int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+       return 0;
+}
+
+void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu)
+{
+}
+
+void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu)
+{
+}
+
+int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+       return 0;
+}
+
+int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+       return 0;
+}
+
+bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+       return false;
+}
+
+vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
+{
+       return VM_FAULT_SIGBUS;
+}
+
+long kvm_arch_vcpu_async_ioctl(struct file *filp,
+                              unsigned int ioctl, unsigned long arg)
+{
+       /* TODO; */
+       return -ENOIOCTLCMD;
+}
+
+long kvm_arch_vcpu_ioctl(struct file *filp,
+                        unsigned int ioctl, unsigned long arg)
+{
+       /* TODO: */
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
+                                 struct kvm_sregs *sregs)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
+                                 struct kvm_sregs *sregs)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
+                                 struct kvm_translation *tr)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
+{
+       return -EINVAL;
+}
+
+int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
+                                   struct kvm_mp_state *mp_state)
+{
+       /* TODO: */
+       return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
+                                   struct kvm_mp_state *mp_state)
+{
+       /* TODO: */
+       return 0;
+}
+
+int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
+                                       struct kvm_guest_debug *dbg)
+{
+       /* TODO; To be implemented later. */
+       return -EINVAL;
+}
+
+void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
+{
+       /* TODO: */
+
+       kvm_riscv_stage2_update_hgatp(vcpu);
+}
+
+void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+}
+
+static void kvm_riscv_check_vcpu_requests(struct kvm_vcpu *vcpu)
+{
+       /* TODO: */
+}
+
+int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
+{
+       int ret;
+       struct kvm_cpu_trap trap;
+       struct kvm_run *run = vcpu->run;
+
+       vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+       /* Process MMIO value returned from user-space */
+       if (run->exit_reason == KVM_EXIT_MMIO) {
+               ret = kvm_riscv_vcpu_mmio_return(vcpu, vcpu->run);
+               if (ret) {
+                       srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+                       return ret;
+               }
+       }
+
+       if (run->immediate_exit) {
+               srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+               return -EINTR;
+       }
+
+       vcpu_load(vcpu);
+
+       kvm_sigset_activate(vcpu);
+
+       ret = 1;
+       run->exit_reason = KVM_EXIT_UNKNOWN;
+       while (ret > 0) {
+               /* Check conditions before entering the guest */
+               cond_resched();
+
+               kvm_riscv_check_vcpu_requests(vcpu);
+
+               preempt_disable();
+
+               local_irq_disable();
+
+               /*
+                * Exit if we have a signal pending so that we can deliver
+                * the signal to user space.
+                */
+               if (signal_pending(current)) {
+                       ret = -EINTR;
+                       run->exit_reason = KVM_EXIT_INTR;
+               }
+
+               /*
+                * Ensure we set mode to IN_GUEST_MODE after we disable
+                * interrupts and before the final VCPU requests check.
+                * See the comment in kvm_vcpu_exiting_guest_mode() and
+                * Documentation/virtual/kvm/vcpu-requests.rst
+                */
+               vcpu->mode = IN_GUEST_MODE;
+
+               srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+               smp_mb__after_srcu_read_unlock();
+
+               if (ret <= 0 ||
+                   kvm_request_pending(vcpu)) {
+                       vcpu->mode = OUTSIDE_GUEST_MODE;
+                       local_irq_enable();
+                       preempt_enable();
+                       vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+                       continue;
+               }
+
+               guest_enter_irqoff();
+
+               __kvm_riscv_switch_to(&vcpu->arch);
+
+               vcpu->mode = OUTSIDE_GUEST_MODE;
+               vcpu->stat.exits++;
+
+               /*
+                * Save SCAUSE, STVAL, HTVAL, and HTINST because we might
+                * get an interrupt between __kvm_riscv_switch_to() and
+                * local_irq_enable() which can potentially change CSRs.
+                */
+               trap.sepc = 0;
+               trap.scause = csr_read(CSR_SCAUSE);
+               trap.stval = csr_read(CSR_STVAL);
+               trap.htval = csr_read(CSR_HTVAL);
+               trap.htinst = csr_read(CSR_HTINST);
+
+               /*
+                * We may have taken a host interrupt in VS/VU-mode (i.e.
+                * while executing the guest). This interrupt is still
+                * pending, as we haven't serviced it yet!
+                *
+                * We're now back in HS-mode with interrupts disabled
+                * so enabling the interrupts now will have the effect
+                * of taking the interrupt again, in HS-mode this time.
+                */
+               local_irq_enable();
+
+               /*
+                * We do local_irq_enable() before calling guest_exit() so
+                * that if a timer interrupt hits while running the guest
+                * we account that tick as being spent in the guest. We
+                * enable preemption after calling guest_exit() so that if
+                * we get preempted we make sure ticks after that is not
+                * counted as guest time.
+                */
+               guest_exit();
+
+               preempt_enable();
+
+               vcpu->arch.srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
+
+               ret = kvm_riscv_vcpu_exit(vcpu, run, &trap);
+       }
+
+       kvm_sigset_deactivate(vcpu);
+
+       vcpu_put(vcpu);
+
+       srcu_read_unlock(&vcpu->kvm->srcu, vcpu->arch.srcu_idx);
+
+       return ret;
+}

diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
new file mode 100644 (file)
index 0000000..4484e92
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kvm_host.h>
+
+/**
+ * kvm_riscv_vcpu_mmio_return -- Handle MMIO loads after user space emulation
+ *                          or in-kernel IO emulation
+ *
+ * @vcpu: The VCPU pointer
+ * @run:  The VCPU run struct containing the mmio data
+ */
+int kvm_riscv_vcpu_mmio_return(struct kvm_vcpu *vcpu, struct kvm_run *run)
+{
+       /* TODO: */
+       return 0;
+}
+
+/*
+ * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
+ * proper exit to userspace.
+ */
+int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run,
+                       struct kvm_cpu_trap *trap)
+{
+       /* TODO: */
+       return 0;
+}

diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c
new file mode 100644 (file)
index 0000000..2249080
--- /dev/null
+++ b/arch/riscv/kvm/vm.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Anup Patel <anup.patel@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/kvm_host.h>
+
+const struct _kvm_stats_desc kvm_vm_stats_desc[] = {
+       KVM_GENERIC_VM_STATS()
+};
+static_assert(ARRAY_SIZE(kvm_vm_stats_desc) ==
+               sizeof(struct kvm_vm_stat) / sizeof(u64));
+
+const struct kvm_stats_header kvm_vm_stats_header = {
+       .name_size = KVM_STATS_NAME_SIZE,
+       .num_desc = ARRAY_SIZE(kvm_vm_stats_desc),
+       .id_offset =  sizeof(struct kvm_stats_header),
+       .desc_offset = sizeof(struct kvm_stats_header) + KVM_STATS_NAME_SIZE,
+       .data_offset = sizeof(struct kvm_stats_header) + KVM_STATS_NAME_SIZE +
+                      sizeof(kvm_vm_stats_desc),
+};
+
+int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+{
+       /* TODO: To be added later. */
+       return -EOPNOTSUPP;
+}
+
+int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
+{
+       int r;
+
+       r = kvm_riscv_stage2_alloc_pgd(kvm);
+       if (r)
+               return r;
+
+       return 0;
+}
+
+void kvm_arch_destroy_vm(struct kvm *kvm)
+{
+       int i;
+
+       for (i = 0; i < KVM_MAX_VCPUS; ++i) {
+               if (kvm->vcpus[i]) {
+                       kvm_vcpu_destroy(kvm->vcpus[i]);
+                       kvm->vcpus[i] = NULL;
+               }
+       }
+       atomic_set(&kvm->online_vcpus, 0);
+}
+
+int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
+{
+       int r;
+
+       switch (ext) {
+       case KVM_CAP_DEVICE_CTRL:
+       case KVM_CAP_USER_MEMORY:
+       case KVM_CAP_DESTROY_MEMORY_REGION_WORKS:
+       case KVM_CAP_ONE_REG:
+       case KVM_CAP_READONLY_MEM:
+       case KVM_CAP_MP_STATE:
+       case KVM_CAP_IMMEDIATE_EXIT:
+               r = 1;
+               break;
+       case KVM_CAP_NR_VCPUS:
+               r = num_online_cpus();
+               break;
+       case KVM_CAP_MAX_VCPUS:
+               r = KVM_MAX_VCPUS;
+               break;
+       case KVM_CAP_NR_MEMSLOTS:
+               r = KVM_USER_MEM_SLOTS;
+               break;
+       default:
+               r = 0;
+               break;
+       }
+
+       return r;
+}
+
+long kvm_arch_vm_ioctl(struct file *filp,
+                      unsigned int ioctl, unsigned long arg)
+{
+       return -EINVAL;
+}