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KVM: selftests: evmcs_test: Check that VMCS12 is alway properly synced to eVMCS after restore

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Add a test for the regression, introduced by commit f2c7ef3ba9
("KVM: nSVM: cancel KVM_REQ_GET_NESTED_STATE_PAGES on nested vmexit"). When
L2->L1 exit is forced immediately after restoring nested state,
KVM_REQ_GET_NESTED_STATE_PAGES request is cleared and VMCS12 changes
(e.g. fresh RIP) are not reflected to eVMCS. The consequent nested
vCPU run gets broken.

Utilize NMI injection to do the job.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210505151823.1341678-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Vitaly Kuznetsov 2021-05-05 17:18:22 +02:00 committed by Paolo Bonzini
parent 32d1b3ab58
commit c9ecafaf01
1 changed files with 55 additions and 11 deletions
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66
tools/testing/selftests/kvm/x86_64/evmcs_test.c
View File

@ -18,30 +18,52 @@
#include "vmx.h"
#define VCPU_ID 5
#define NMI_VECTOR 2
static int ud_count;
void enable_x2apic(void)
{
uint32_t spiv_reg = APIC_BASE_MSR + (APIC_SPIV >> 4);
wrmsr(MSR_IA32_APICBASE, rdmsr(MSR_IA32_APICBASE) |
MSR_IA32_APICBASE_ENABLE | MSR_IA32_APICBASE_EXTD);
wrmsr(spiv_reg, rdmsr(spiv_reg) | APIC_SPIV_APIC_ENABLED);
}
static void guest_ud_handler(struct ex_regs *regs)
{
ud_count++;
regs->rip += 3; /* VMLAUNCH */
}
static void guest_nmi_handler(struct ex_regs *regs)
{
}
void l2_guest_code(void)
{
GUEST_SYNC(7);
GUEST_SYNC(8);
/* Forced exit to L1 upon restore */
GUEST_SYNC(9);
/* Done, exit to L1 and never come back. */
vmcall();
}
void l1_guest_code(struct vmx_pages *vmx_pages)
void guest_code(struct vmx_pages *vmx_pages)
{
#define L2_GUEST_STACK_SIZE 64
unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
enable_x2apic();
GUEST_SYNC(1);
GUEST_SYNC(2);
enable_vp_assist(vmx_pages->vp_assist_gpa, vmx_pages->vp_assist);
GUEST_ASSERT(vmx_pages->vmcs_gpa);
@ -63,21 +85,22 @@ void l1_guest_code(struct vmx_pages *vmx_pages)
current_evmcs->revision_id = EVMCS_VERSION;
GUEST_SYNC(6);
current_evmcs->pin_based_vm_exec_control |=
PIN_BASED_NMI_EXITING;
GUEST_ASSERT(!vmlaunch());
GUEST_ASSERT(vmptrstz() == vmx_pages->enlightened_vmcs_gpa);
GUEST_SYNC(9);
/*
* NMI forces L2->L1 exit, resuming L2 and hope that EVMCS is
* up-to-date (RIP points where it should and not at the beginning
* of l2_guest_code(). GUEST_SYNC(9) checkes that.
*/
GUEST_ASSERT(!vmresume());
GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
GUEST_SYNC(10);
}
void guest_code(struct vmx_pages *vmx_pages)
{
GUEST_SYNC(1);
GUEST_SYNC(2);
if (vmx_pages)
l1_guest_code(vmx_pages);
GUEST_ASSERT(vmreadz(VM_EXIT_REASON) == EXIT_REASON_VMCALL);
GUEST_SYNC(11);
/* Try enlightened vmptrld with an incorrect GPA */
evmcs_vmptrld(0xdeadbeef, vmx_pages->enlightened_vmcs);
@ -86,6 +109,18 @@ void guest_code(struct vmx_pages *vmx_pages)
GUEST_DONE();
}
void inject_nmi(struct kvm_vm *vm)
{
struct kvm_vcpu_events events;
vcpu_events_get(vm, VCPU_ID, &events);
events.nmi.pending = 1;
events.flags |= KVM_VCPUEVENT_VALID_NMI_PENDING;
vcpu_events_set(vm, VCPU_ID, &events);
}
int main(int argc, char *argv[])
{
vm_vaddr_t vmx_pages_gva = 0;
@ -120,6 +155,9 @@ int main(int argc, char *argv[])
vm_init_descriptor_tables(vm);
vcpu_init_descriptor_tables(vm, VCPU_ID);
vm_handle_exception(vm, UD_VECTOR, guest_ud_handler);
vm_handle_exception(vm, NMI_VECTOR, guest_nmi_handler);
pr_info("Running L1 which uses EVMCS to run L2\n");
for (stage = 1;; stage++) {
_vcpu_run(vm, VCPU_ID);
@ -166,6 +204,12 @@ int main(int argc, char *argv[])
TEST_ASSERT(!memcmp(&regs1, &regs2, sizeof(regs2)),
"Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
(ulong) regs2.rdi, (ulong) regs2.rsi);
/* Force immediate L2->L1 exit before resuming */
if (stage == 8) {
pr_info("Injecting NMI into L1 before L2 had a chance to run after restore\n");
inject_nmi(vm);
}
}
done: