Commit e67bd7df authored by Vitaly Kuznetsov's avatar Vitaly Kuznetsov Committed by Paolo Bonzini

KVM: selftests: nSVM: Add enlightened MSR-Bitmap selftest

Introduce a new test for Hyper-V nSVM extensions (Hyper-V on KVM) and add
a test for enlightened MSR-Bitmap feature:

- Intercept access to MSR_FS_BASE in L1 and check that this works
  with enlightened MSR-Bitmap disabled.
- Enabled enlightened MSR-Bitmap and check that the intercept still works
  as expected.
- Intercept access to MSR_GS_BASE but don't clear the corresponding bit
  from clean fields mask, KVM is supposed to skip updating MSR-Bitmap02 and
  thus the consequent access to the MSR from L2 will not get intercepted.
- Finally, clear the corresponding bit from clean fields mask and check
  that access to MSR_GS_BASE is now intercepted.

The test works with the assumption, that access to MSR_FS_BASE/MSR_GS_BASE
is not intercepted for L1. If this ever becomes not true the test will
fail as nested_svm_exit_handled_msr() always checks L1's MSR-Bitmap for
L2 irrespective of clean fields. The behavior is correct as enlightened
MSR-Bitmap feature is just an optimization, KVM is not obliged to ignore
updates when the corresponding bit in clean fields stays clear.
Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20220203104620.277031-7-vkuznets@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 29f557d5
...@@ -51,6 +51,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/emulator_error_test ...@@ -51,6 +51,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/emulator_error_test
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_clock TEST_GEN_PROGS_x86_64 += x86_64/hyperv_clock
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_features TEST_GEN_PROGS_x86_64 += x86_64/hyperv_features
TEST_GEN_PROGS_x86_64 += x86_64/hyperv_svm_test
TEST_GEN_PROGS_x86_64 += x86_64/kvm_clock_test TEST_GEN_PROGS_x86_64 += x86_64/kvm_clock_test
TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test
TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test
......
...@@ -16,6 +16,7 @@ ...@@ -16,6 +16,7 @@
#define CPUID_SVM_BIT 2 #define CPUID_SVM_BIT 2
#define CPUID_SVM BIT_ULL(CPUID_SVM_BIT) #define CPUID_SVM BIT_ULL(CPUID_SVM_BIT)
#define SVM_EXIT_MSR 0x07c
#define SVM_EXIT_VMMCALL 0x081 #define SVM_EXIT_VMMCALL 0x081
struct svm_test_data { struct svm_test_data {
......
// SPDX-License-Identifier: GPL-2.0-only
/*
* KVM_GET/SET_* tests
*
* Copyright (C) 2022, Red Hat, Inc.
*
* Tests for Hyper-V extensions to SVM.
*/
#define _GNU_SOURCE /* for program_invocation_short_name */
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/bitmap.h>
#include "test_util.h"
#include "kvm_util.h"
#include "processor.h"
#include "svm_util.h"
#include "hyperv.h"
#define VCPU_ID 1
#define L2_GUEST_STACK_SIZE 256
struct hv_enlightenments {
struct __packed hv_enlightenments_control {
u32 nested_flush_hypercall:1;
u32 msr_bitmap:1;
u32 enlightened_npt_tlb: 1;
u32 reserved:29;
} __packed hv_enlightenments_control;
u32 hv_vp_id;
u64 hv_vm_id;
u64 partition_assist_page;
u64 reserved;
} __packed;
/*
* Hyper-V uses the software reserved clean bit in VMCB
*/
#define VMCB_HV_NESTED_ENLIGHTENMENTS (1U << 31)
static inline void vmmcall(void)
{
__asm__ __volatile__("vmmcall");
}
void l2_guest_code(void)
{
GUEST_SYNC(3);
/* Exit to L1 */
vmmcall();
/* MSR-Bitmap tests */
rdmsr(MSR_FS_BASE); /* intercepted */
rdmsr(MSR_FS_BASE); /* intercepted */
rdmsr(MSR_GS_BASE); /* not intercepted */
vmmcall();
rdmsr(MSR_GS_BASE); /* intercepted */
GUEST_SYNC(5);
/* Done, exit to L1 and never come back. */
vmmcall();
}
static void __attribute__((__flatten__)) guest_code(struct svm_test_data *svm)
{
unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
struct vmcb *vmcb = svm->vmcb;
struct hv_enlightenments *hve =
(struct hv_enlightenments *)vmcb->control.reserved_sw;
GUEST_SYNC(1);
wrmsr(HV_X64_MSR_GUEST_OS_ID, (u64)0x8100 << 48);
GUEST_ASSERT(svm->vmcb_gpa);
/* Prepare for L2 execution. */
generic_svm_setup(svm, l2_guest_code,
&l2_guest_stack[L2_GUEST_STACK_SIZE]);
GUEST_SYNC(2);
run_guest(vmcb, svm->vmcb_gpa);
GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
GUEST_SYNC(4);
vmcb->save.rip += 3;
/* Intercept RDMSR 0xc0000100 */
vmcb->control.intercept |= 1ULL << INTERCEPT_MSR_PROT;
set_bit(2 * (MSR_FS_BASE & 0x1fff), svm->msr + 0x800);
run_guest(vmcb, svm->vmcb_gpa);
GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
vmcb->save.rip += 2; /* rdmsr */
/* Enable enlightened MSR bitmap */
hve->hv_enlightenments_control.msr_bitmap = 1;
run_guest(vmcb, svm->vmcb_gpa);
GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
vmcb->save.rip += 2; /* rdmsr */
/* Intercept RDMSR 0xc0000101 without telling KVM about it */
set_bit(2 * (MSR_GS_BASE & 0x1fff), svm->msr + 0x800);
/* Make sure HV_VMX_ENLIGHTENED_CLEAN_FIELD_MSR_BITMAP is set */
vmcb->control.clean |= VMCB_HV_NESTED_ENLIGHTENMENTS;
run_guest(vmcb, svm->vmcb_gpa);
/* Make sure we don't see SVM_EXIT_MSR here so eMSR bitmap works */
GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
vmcb->save.rip += 3; /* vmcall */
/* Now tell KVM we've changed MSR-Bitmap */
vmcb->control.clean &= ~VMCB_HV_NESTED_ENLIGHTENMENTS;
run_guest(vmcb, svm->vmcb_gpa);
GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_MSR);
vmcb->save.rip += 2; /* rdmsr */
run_guest(vmcb, svm->vmcb_gpa);
GUEST_ASSERT(vmcb->control.exit_code == SVM_EXIT_VMMCALL);
GUEST_SYNC(6);
GUEST_DONE();
}
int main(int argc, char *argv[])
{
vm_vaddr_t nested_gva = 0;
struct kvm_vm *vm;
struct kvm_run *run;
struct ucall uc;
int stage;
if (!nested_svm_supported()) {
print_skip("Nested SVM not supported");
exit(KSFT_SKIP);
}
/* Create VM */
vm = vm_create_default(VCPU_ID, 0, guest_code);
vcpu_set_hv_cpuid(vm, VCPU_ID);
run = vcpu_state(vm, VCPU_ID);
vcpu_alloc_svm(vm, &nested_gva);
vcpu_args_set(vm, VCPU_ID, 1, nested_gva);
for (stage = 1;; stage++) {
_vcpu_run(vm, VCPU_ID);
TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
"Stage %d: unexpected exit reason: %u (%s),\n",
stage, run->exit_reason,
exit_reason_str(run->exit_reason));
switch (get_ucall(vm, VCPU_ID, &uc)) {
case UCALL_ABORT:
TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0],
__FILE__, uc.args[1]);
/* NOT REACHED */
case UCALL_SYNC:
break;
case UCALL_DONE:
goto done;
default:
TEST_FAIL("Unknown ucall %lu", uc.cmd);
}
/* UCALL_SYNC is handled here. */
TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") &&
uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
stage, (ulong)uc.args[1]);
}
done:
kvm_vm_free(vm);
}
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