* [PATCH 0/3] KVM: selftests: evmcs_test: Check issues induced by late eVMCS mapping upon restore
@ 2021-05-05 15:18 Vitaly Kuznetsov
2021-05-05 15:18 ` [PATCH 1/3] KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is causing #UD Vitaly Kuznetsov
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: Vitaly Kuznetsov @ 2021-05-05 15:18 UTC (permalink / raw)
To: kvm, Paolo Bonzini
Cc: Sean Christopherson, Wanpeng Li, Jim Mattson, Maxim Levitsky,
linux-kernel
A regression was introduced by commit f2c7ef3ba955
("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. Add a test for the condition (PATCH2). PATCH1 is a preparatory
change, PATCH3 adds a test for a situation when KVM_GET_NESTED_STATE is
requested right after KVM_SET_NESTED_STATE, this is still broken in KVM
(so the patch is not to be committed).
Vitaly Kuznetsov (3):
KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is
causing #UD
KVM: selftests: evmcs_test: Check that VMCS12 is alway properly synced
to eVMCS after restore
KVM: selftests: evmcs_test: Test that KVM_STATE_NESTED_EVMCS is never
lost
.../testing/selftests/kvm/x86_64/evmcs_test.c | 150 +++++++++++++-----
1 file changed, 108 insertions(+), 42 deletions(-)
--
2.30.2
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/3] KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is causing #UD
2021-05-05 15:18 [PATCH 0/3] KVM: selftests: evmcs_test: Check issues induced by late eVMCS mapping upon restore Vitaly Kuznetsov
@ 2021-05-05 15:18 ` Vitaly Kuznetsov
2021-05-05 15:18 ` [PATCH 2/3] KVM: selftests: evmcs_test: Check that VMCS12 is alway properly synced to eVMCS after restore Vitaly Kuznetsov
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Vitaly Kuznetsov @ 2021-05-05 15:18 UTC (permalink / raw)
To: kvm, Paolo Bonzini
Cc: Sean Christopherson, Wanpeng Li, Jim Mattson, Maxim Levitsky,
linux-kernel
'run->exit_reason == KVM_EXIT_SHUTDOWN' check is not ideal as we may be
getting some unexpected exception. Directly check for #UD instead.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
.../testing/selftests/kvm/x86_64/evmcs_test.c | 24 ++++++++++++-------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/evmcs_test.c b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
index ca22ee6d19cb..b01f64ac6ce3 100644
--- a/tools/testing/selftests/kvm/x86_64/evmcs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
@@ -19,6 +19,14 @@
#define VCPU_ID 5
+static int ud_count;
+
+static void guest_ud_handler(struct ex_regs *regs)
+{
+ ud_count++;
+ regs->rip += 3; /* VMLAUNCH */
+}
+
void l2_guest_code(void)
{
GUEST_SYNC(7);
@@ -71,11 +79,11 @@ void guest_code(struct vmx_pages *vmx_pages)
if (vmx_pages)
l1_guest_code(vmx_pages);
- GUEST_DONE();
-
/* Try enlightened vmptrld with an incorrect GPA */
evmcs_vmptrld(0xdeadbeef, vmx_pages->enlightened_vmcs);
GUEST_ASSERT(vmlaunch());
+ GUEST_ASSERT(ud_count == 1);
+ GUEST_DONE();
}
int main(int argc, char *argv[])
@@ -109,6 +117,10 @@ int main(int argc, char *argv[])
vcpu_alloc_vmx(vm, &vmx_pages_gva);
vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
+ vm_init_descriptor_tables(vm);
+ vcpu_init_descriptor_tables(vm, VCPU_ID);
+ vm_handle_exception(vm, UD_VECTOR, guest_ud_handler);
+
for (stage = 1;; stage++) {
_vcpu_run(vm, VCPU_ID);
TEST_ASSERT(run->exit_reason == KVM_EXIT_IO,
@@ -124,7 +136,7 @@ int main(int argc, char *argv[])
case UCALL_SYNC:
break;
case UCALL_DONE:
- goto part1_done;
+ goto done;
default:
TEST_FAIL("Unknown ucall %lu", uc.cmd);
}
@@ -156,10 +168,6 @@ int main(int argc, char *argv[])
(ulong) regs2.rdi, (ulong) regs2.rsi);
}
-part1_done:
- _vcpu_run(vm, VCPU_ID);
- TEST_ASSERT(run->exit_reason == KVM_EXIT_SHUTDOWN,
- "Unexpected successful VMEnter with invalid eVMCS pointer!");
-
+done:
kvm_vm_free(vm);
}
--
2.30.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/3] KVM: selftests: evmcs_test: Check that VMCS12 is alway properly synced to eVMCS after restore
2021-05-05 15:18 [PATCH 0/3] KVM: selftests: evmcs_test: Check issues induced by late eVMCS mapping upon restore Vitaly Kuznetsov
2021-05-05 15:18 ` [PATCH 1/3] KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is causing #UD Vitaly Kuznetsov
@ 2021-05-05 15:18 ` Vitaly Kuznetsov
2021-05-05 15:18 ` [PATCH 3/3] KVM: selftests: evmcs_test: Test that KVM_STATE_NESTED_EVMCS is never lost Vitaly Kuznetsov
2021-05-05 15:44 ` [PATCH 0/3] KVM: selftests: evmcs_test: Check issues induced by late eVMCS mapping upon restore Paolo Bonzini
3 siblings, 0 replies; 5+ messages in thread
From: Vitaly Kuznetsov @ 2021-05-05 15:18 UTC (permalink / raw)
To: kvm, Paolo Bonzini
Cc: Sean Christopherson, Wanpeng Li, Jim Mattson, Maxim Levitsky,
linux-kernel
Add a test for the regression, introduced by commit f2c7ef3ba955
("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>
---
.../testing/selftests/kvm/x86_64/evmcs_test.c | 66 +++++++++++++++----
1 file changed, 55 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/evmcs_test.c b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
index b01f64ac6ce3..63096cea26c6 100644
--- a/tools/testing/selftests/kvm/x86_64/evmcs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
@@ -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);
+ GUEST_SYNC(10);
- 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(®s1, ®s2, 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:
--
2.30.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 3/3] KVM: selftests: evmcs_test: Test that KVM_STATE_NESTED_EVMCS is never lost
2021-05-05 15:18 [PATCH 0/3] KVM: selftests: evmcs_test: Check issues induced by late eVMCS mapping upon restore Vitaly Kuznetsov
2021-05-05 15:18 ` [PATCH 1/3] KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is causing #UD Vitaly Kuznetsov
2021-05-05 15:18 ` [PATCH 2/3] KVM: selftests: evmcs_test: Check that VMCS12 is alway properly synced to eVMCS after restore Vitaly Kuznetsov
@ 2021-05-05 15:18 ` Vitaly Kuznetsov
2021-05-05 15:44 ` [PATCH 0/3] KVM: selftests: evmcs_test: Check issues induced by late eVMCS mapping upon restore Paolo Bonzini
3 siblings, 0 replies; 5+ messages in thread
From: Vitaly Kuznetsov @ 2021-05-05 15:18 UTC (permalink / raw)
To: kvm, Paolo Bonzini
Cc: Sean Christopherson, Wanpeng Li, Jim Mattson, Maxim Levitsky,
linux-kernel
Do KVM_GET_NESTED_STATE/KVM_SET_NESTED_STATE for a freshly restored VM
(before the first KVM_RUN) to check that KVM_STATE_NESTED_EVMCS is not
lost.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
- Note: this test is not yet to be commited as it is known to fail. A
patch like
https://lore.kernel.org/kvm/877dkdy1x5.fsf@vitty.brq.redhat.com/T/#u
is needed to make it pass. The patch itself requires more work.
---
.../testing/selftests/kvm/x86_64/evmcs_test.c | 62 ++++++++++++-------
1 file changed, 38 insertions(+), 24 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/evmcs_test.c b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
index 63096cea26c6..8d1a63da5c63 100644
--- a/tools/testing/selftests/kvm/x86_64/evmcs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/evmcs_test.c
@@ -121,14 +121,39 @@ void inject_nmi(struct kvm_vm *vm)
vcpu_events_set(vm, VCPU_ID, &events);
}
+static void save_restore_vm(struct kvm_vm *vm, struct kvm_run *run)
+{
+ struct kvm_regs regs1, regs2;
+ struct kvm_x86_state *state;
+
+ state = vcpu_save_state(vm, VCPU_ID);
+ memset(®s1, 0, sizeof(regs1));
+ vcpu_regs_get(vm, VCPU_ID, ®s1);
+
+ kvm_vm_release(vm);
+
+ /* Restore state in a new VM. */
+ kvm_vm_restart(vm, O_RDWR);
+ vm_vcpu_add(vm, VCPU_ID);
+ vcpu_set_hv_cpuid(vm, VCPU_ID);
+ vcpu_enable_evmcs(vm, VCPU_ID);
+ vcpu_load_state(vm, VCPU_ID, state);
+ run = vcpu_state(vm, VCPU_ID);
+ free(state);
+
+ memset(®s2, 0, sizeof(regs2));
+ vcpu_regs_get(vm, VCPU_ID, ®s2);
+ TEST_ASSERT(!memcmp(®s1, ®s2, sizeof(regs2)),
+ "Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
+ (ulong) regs2.rdi, (ulong) regs2.rsi);
+}
+
int main(int argc, char *argv[])
{
vm_vaddr_t vmx_pages_gva = 0;
- struct kvm_regs regs1, regs2;
struct kvm_vm *vm;
struct kvm_run *run;
- struct kvm_x86_state *state;
struct ucall uc;
int stage;
@@ -147,8 +172,6 @@ int main(int argc, char *argv[])
run = vcpu_state(vm, VCPU_ID);
- vcpu_regs_get(vm, VCPU_ID, ®s1);
-
vcpu_alloc_vmx(vm, &vmx_pages_gva);
vcpu_args_set(vm, VCPU_ID, 1, vmx_pages_gva);
@@ -184,32 +207,23 @@ int main(int argc, char *argv[])
uc.args[1] == stage, "Stage %d: Unexpected register values vmexit, got %lx",
stage, (ulong)uc.args[1]);
- state = vcpu_save_state(vm, VCPU_ID);
- memset(®s1, 0, sizeof(regs1));
- vcpu_regs_get(vm, VCPU_ID, ®s1);
-
- kvm_vm_release(vm);
-
- /* Restore state in a new VM. */
- kvm_vm_restart(vm, O_RDWR);
- vm_vcpu_add(vm, VCPU_ID);
- vcpu_set_hv_cpuid(vm, VCPU_ID);
- vcpu_enable_evmcs(vm, VCPU_ID);
- vcpu_load_state(vm, VCPU_ID, state);
- run = vcpu_state(vm, VCPU_ID);
- free(state);
-
- memset(®s2, 0, sizeof(regs2));
- vcpu_regs_get(vm, VCPU_ID, ®s2);
- TEST_ASSERT(!memcmp(®s1, ®s2, sizeof(regs2)),
- "Unexpected register values after vcpu_load_state; rdi: %lx rsi: %lx",
- (ulong) regs2.rdi, (ulong) regs2.rsi);
+ save_restore_vm(vm, run);
/* 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);
}
+
+ /*
+ * Do KVM_GET_NESTED_STATE/KVM_SET_NESTED_STATE for a freshly
+ * restored VM (before the first KVM_RUN) to check that
+ * KVM_STATE_NESTED_EVMCS is not lost.
+ */
+ if (stage == 9) {
+ pr_info("Trying extra KVM_GET_NESTED_STATE/KVM_SET_NESTED_STATE cycle\n");
+ save_restore_vm(vm, run);
+ }
}
done:
--
2.30.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 0/3] KVM: selftests: evmcs_test: Check issues induced by late eVMCS mapping upon restore
2021-05-05 15:18 [PATCH 0/3] KVM: selftests: evmcs_test: Check issues induced by late eVMCS mapping upon restore Vitaly Kuznetsov
` (2 preceding siblings ...)
2021-05-05 15:18 ` [PATCH 3/3] KVM: selftests: evmcs_test: Test that KVM_STATE_NESTED_EVMCS is never lost Vitaly Kuznetsov
@ 2021-05-05 15:44 ` Paolo Bonzini
3 siblings, 0 replies; 5+ messages in thread
From: Paolo Bonzini @ 2021-05-05 15:44 UTC (permalink / raw)
To: Vitaly Kuznetsov, kvm
Cc: Sean Christopherson, Wanpeng Li, Jim Mattson, Maxim Levitsky,
linux-kernel
On 05/05/21 17:18, Vitaly Kuznetsov wrote:
> A regression was introduced by commit f2c7ef3ba955
> ("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. Add a test for the condition (PATCH2). PATCH1 is a preparatory
> change, PATCH3 adds a test for a situation when KVM_GET_NESTED_STATE is
> requested right after KVM_SET_NESTED_STATE, this is still broken in KVM
> (so the patch is not to be committed).
>
> Vitaly Kuznetsov (3):
> KVM: selftests: evmcs_test: Check that VMLAUNCH with bogus EVMPTR is
> causing #UD
> KVM: selftests: evmcs_test: Check that VMCS12 is alway properly synced
> to eVMCS after restore
> KVM: selftests: evmcs_test: Test that KVM_STATE_NESTED_EVMCS is never
> lost
>
> .../testing/selftests/kvm/x86_64/evmcs_test.c | 150 +++++++++++++-----
> 1 file changed, 108 insertions(+), 42 deletions(-)
>
Queued 1-2, thanks.
Paolo
^ permalink raw reply [flat|nested] 5+ messages in thread
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