* [kvm-unit-tests PATCH v2] x86: nvmx: test max atomic switch MSRs
@ 2019-09-14 0:49 Marc Orr
2019-09-16 19:06 ` Krish Sadhukhan
0 siblings, 1 reply; 4+ messages in thread
From: Marc Orr @ 2019-09-14 0:49 UTC (permalink / raw)
To: kvm, jmattson, pshier, sean.j.christopherson; +Cc: Marc Orr
Excerise nested VMX's atomic MSR switch code (e.g., VM-entry MSR-load
list) at the maximum number of MSRs supported, as described in the SDM,
in the appendix chapter titled "MISCELLANEOUS DATA".
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Marc Orr <marcorr@google.com>
---
v1 -> v2
* Replaced 2M page allocations with 128 kB allocations.
* Broadly, updated test to follow Sean's draft:
* Got rid of loop + individual test cases. Instead combined all test cases.
* Got rid of configure_atomic_switch_msr_limit_test().
* Updated cleanup code to free memory. I added a new helper,
free_pages_by_order() to help here.
* Changed virt_to_phys() to explicit u64 cast.
* Renamed original test case from atomic_switch_msr_limit_test() to
atomic_switch_max_msrs_test(). Added opt-in
atomic_switch_overflow_msrs_test() test case to test failure code path
during VM-entry.
* Fixed a bug in transitioning VMX launched state when the first
VM-entry fails.
lib/alloc_page.c | 5 ++
lib/alloc_page.h | 1 +
x86/unittests.cfg | 2 +-
x86/vmx.c | 2 +-
x86/vmx_tests.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 139 insertions(+), 2 deletions(-)
diff --git a/lib/alloc_page.c b/lib/alloc_page.c
index 97d13395ff08..ed236389537e 100644
--- a/lib/alloc_page.c
+++ b/lib/alloc_page.c
@@ -53,6 +53,11 @@ void free_pages(void *mem, unsigned long size)
spin_unlock(&lock);
}
+void free_pages_by_order(void *mem, unsigned long order)
+{
+ free_pages(mem, 1ul << (order + PAGE_SHIFT));
+}
+
void *alloc_page()
{
void *p;
diff --git a/lib/alloc_page.h b/lib/alloc_page.h
index 5cdfec57a0a8..739a91def979 100644
--- a/lib/alloc_page.h
+++ b/lib/alloc_page.h
@@ -14,5 +14,6 @@ void *alloc_page(void);
void *alloc_pages(unsigned long order);
void free_page(void *page);
void free_pages(void *mem, unsigned long size);
+void free_pages_by_order(void *mem, unsigned long order);
#endif
diff --git a/x86/unittests.cfg b/x86/unittests.cfg
index 694ee3d42f3a..05122cf91ea1 100644
--- a/x86/unittests.cfg
+++ b/x86/unittests.cfg
@@ -227,7 +227,7 @@ extra_params = -cpu qemu64,+umip
[vmx]
file = vmx.flat
-extra_params = -cpu host,+vmx -append "-exit_monitor_from_l2_test -ept_access* -vmx_smp* -vmx_vmcs_shadow_test"
+extra_params = -cpu host,+vmx -append "-exit_monitor_from_l2_test -ept_access* -vmx_smp* -vmx_vmcs_shadow_test -atomic_switch_overflow_msrs_test"
arch = x86_64
groups = vmx
diff --git a/x86/vmx.c b/x86/vmx.c
index 6079420db33a..7313c78f15c2 100644
--- a/x86/vmx.c
+++ b/x86/vmx.c
@@ -1820,7 +1820,7 @@ static void __enter_guest(u8 abort_flag, struct vmentry_failure *failure)
abort();
}
- if (!failure->early) {
+ if (!failure->early && !(vmcs_read(EXI_REASON) & VMX_ENTRY_FAILURE)) {
launched = 1;
check_for_guest_termination();
}
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index f035f24a771a..fb665f38b1e5 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -8570,6 +8570,134 @@ static int invalid_msr_entry_failure(struct vmentry_failure *failure)
return VMX_TEST_VMEXIT;
}
+/*
+ * The max number of MSRs in an atomic switch MSR list is:
+ * (111B + 1) * 512 = 4096
+ *
+ * Each list entry consumes:
+ * 4-byte MSR index + 4 bytes reserved + 8-byte data = 16 bytes
+ *
+ * Allocate 128 kB to cover max_msr_list_size (i.e., 64 kB) and then some.
+ */
+static const u32 msr_list_page_order = 5;
+
+static void atomic_switch_msr_limit_test_guest(void)
+{
+ vmcall();
+}
+
+static void populate_msr_list(struct vmx_msr_entry *msr_list,
+ size_t byte_capacity, int count)
+{
+ int i;
+
+ for (i = 0; i < count; i++) {
+ msr_list[i].index = MSR_IA32_TSC;
+ msr_list[i].reserved = 0;
+ msr_list[i].value = 0x1234567890abcdef;
+ }
+
+ memset(msr_list + count, 0xff,
+ byte_capacity - count * sizeof(*msr_list));
+}
+
+static int max_msr_list_size(void)
+{
+ u32 vmx_misc = rdmsr(MSR_IA32_VMX_MISC);
+ u32 factor = ((vmx_misc & GENMASK(27, 25)) >> 25) + 1;
+
+ return factor * 512;
+}
+
+static void atomic_switch_msrs_test(int count)
+{
+ struct vmx_msr_entry *vm_enter_load;
+ struct vmx_msr_entry *vm_exit_load;
+ struct vmx_msr_entry *vm_exit_store;
+ int max_allowed = max_msr_list_size();
+ int byte_capacity = 1ul << (msr_list_page_order + PAGE_SHIFT);
+ /* Exceeding the max MSR list size at exit trigers KVM to abort. */
+ int exit_count = count > max_allowed ? max_allowed : count;
+ int cleanup_count = count > max_allowed ? 2 : 1;
+ int i;
+
+ /*
+ * Check for the IA32_TSC MSR,
+ * available with the "TSC flag" and used to populate the MSR lists.
+ */
+ if (!(cpuid(1).d & (1 << 4))) {
+ report_skip(__func__);
+ return;
+ }
+
+ /* Set L2 guest. */
+ test_set_guest(atomic_switch_msr_limit_test_guest);
+
+ /* Setup atomic MSR switch lists. */
+ vm_enter_load = alloc_pages(msr_list_page_order);
+ vm_exit_load = alloc_pages(msr_list_page_order);
+ vm_exit_store = alloc_pages(msr_list_page_order);
+
+ vmcs_write(ENTER_MSR_LD_ADDR, (u64)vm_enter_load);
+ vmcs_write(EXIT_MSR_LD_ADDR, (u64)vm_exit_load);
+ vmcs_write(EXIT_MSR_ST_ADDR, (u64)vm_exit_store);
+
+ /*
+ * VM-Enter should succeed up to the max number of MSRs per list, and
+ * should not consume junk beyond the last entry.
+ */
+ populate_msr_list(vm_enter_load, byte_capacity, count);
+ populate_msr_list(vm_exit_load, byte_capacity, exit_count);
+ populate_msr_list(vm_exit_store, byte_capacity, exit_count);
+
+ vmcs_write(ENT_MSR_LD_CNT, count);
+ vmcs_write(EXI_MSR_LD_CNT, exit_count);
+ vmcs_write(EXI_MSR_ST_CNT, exit_count);
+
+ if (count <= max_allowed) {
+ enter_guest();
+ assert_exit_reason(VMX_VMCALL);
+ skip_exit_vmcall();
+ } else {
+ u32 exit_reason;
+ u32 exit_reason_want;
+ u32 exit_qual;
+
+ enter_guest_with_invalid_guest_state();
+
+ exit_reason = vmcs_read(EXI_REASON);
+ exit_reason_want = VMX_FAIL_MSR | VMX_ENTRY_FAILURE;
+ report("exit_reason, %u, is %u.",
+ exit_reason == exit_reason_want, exit_reason,
+ exit_reason_want);
+
+ exit_qual = vmcs_read(EXI_QUALIFICATION);
+ report("exit_qual, %u, is %u.", exit_qual == max_allowed + 1,
+ exit_qual, max_allowed + 1);
+ }
+
+ /* Cleanup. */
+ vmcs_write(ENT_MSR_LD_CNT, 0);
+ vmcs_write(EXI_MSR_LD_CNT, 0);
+ vmcs_write(EXI_MSR_ST_CNT, 0);
+ for (i = 0; i < cleanup_count; i++) {
+ enter_guest();
+ skip_exit_vmcall();
+ }
+ free_pages_by_order(vm_enter_load, msr_list_page_order);
+ free_pages_by_order(vm_exit_load, msr_list_page_order);
+ free_pages_by_order(vm_exit_store, msr_list_page_order);
+}
+
+static void atomic_switch_max_msrs_test(void)
+{
+ atomic_switch_msrs_test(max_msr_list_size());
+}
+
+static void atomic_switch_overflow_msrs_test(void)
+{
+ atomic_switch_msrs_test(max_msr_list_size() + 1);
+}
#define TEST(name) { #name, .v2 = name }
@@ -8660,5 +8788,8 @@ struct vmx_test vmx_tests[] = {
TEST(ept_access_test_paddr_read_execute_ad_enabled),
TEST(ept_access_test_paddr_not_present_page_fault),
TEST(ept_access_test_force_2m_page),
+ /* Atomic MSR switch tests. */
+ TEST(atomic_switch_max_msrs_test),
+ TEST(atomic_switch_overflow_msrs_test),
{ NULL, NULL, NULL, NULL, NULL, {0} },
};
--
2.23.0.237.gc6a4ce50a0-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [kvm-unit-tests PATCH v2] x86: nvmx: test max atomic switch MSRs
2019-09-14 0:49 [kvm-unit-tests PATCH v2] x86: nvmx: test max atomic switch MSRs Marc Orr
@ 2019-09-16 19:06 ` Krish Sadhukhan
2019-09-16 21:11 ` Marc Orr
0 siblings, 1 reply; 4+ messages in thread
From: Krish Sadhukhan @ 2019-09-16 19:06 UTC (permalink / raw)
To: Marc Orr, kvm, jmattson, pshier, sean.j.christopherson
On 09/13/2019 05:49 PM, Marc Orr wrote:
> Excerise nested VMX's atomic MSR switch code (e.g., VM-entry MSR-load
> list) at the maximum number of MSRs supported, as described in the SDM,
> in the appendix chapter titled "MISCELLANEOUS DATA".
>
> Suggested-by: Jim Mattson <jmattson@google.com>
> Signed-off-by: Marc Orr <marcorr@google.com>
> ---
> v1 -> v2
> * Replaced 2M page allocations with 128 kB allocations.
> * Broadly, updated test to follow Sean's draft:
> * Got rid of loop + individual test cases. Instead combined all test cases.
> * Got rid of configure_atomic_switch_msr_limit_test().
> * Updated cleanup code to free memory. I added a new helper,
> free_pages_by_order() to help here.
> * Changed virt_to_phys() to explicit u64 cast.
> * Renamed original test case from atomic_switch_msr_limit_test() to
> atomic_switch_max_msrs_test(). Added opt-in
> atomic_switch_overflow_msrs_test() test case to test failure code path
> during VM-entry.
> * Fixed a bug in transitioning VMX launched state when the first
> VM-entry fails.
Can we move this bug-fix to a separate patch so that it can be
identified easily when searching in git history ?
>
> lib/alloc_page.c | 5 ++
> lib/alloc_page.h | 1 +
> x86/unittests.cfg | 2 +-
> x86/vmx.c | 2 +-
> x86/vmx_tests.c | 131 ++++++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 139 insertions(+), 2 deletions(-)
>
> diff --git a/lib/alloc_page.c b/lib/alloc_page.c
> index 97d13395ff08..ed236389537e 100644
> --- a/lib/alloc_page.c
> +++ b/lib/alloc_page.c
> @@ -53,6 +53,11 @@ void free_pages(void *mem, unsigned long size)
> spin_unlock(&lock);
> }
>
> +void free_pages_by_order(void *mem, unsigned long order)
> +{
> + free_pages(mem, 1ul << (order + PAGE_SHIFT));
> +}
> +
> void *alloc_page()
> {
> void *p;
> diff --git a/lib/alloc_page.h b/lib/alloc_page.h
> index 5cdfec57a0a8..739a91def979 100644
> --- a/lib/alloc_page.h
> +++ b/lib/alloc_page.h
> @@ -14,5 +14,6 @@ void *alloc_page(void);
> void *alloc_pages(unsigned long order);
> void free_page(void *page);
> void free_pages(void *mem, unsigned long size);
> +void free_pages_by_order(void *mem, unsigned long order);
>
> #endif
> diff --git a/x86/unittests.cfg b/x86/unittests.cfg
> index 694ee3d42f3a..05122cf91ea1 100644
> --- a/x86/unittests.cfg
> +++ b/x86/unittests.cfg
> @@ -227,7 +227,7 @@ extra_params = -cpu qemu64,+umip
>
> [vmx]
> file = vmx.flat
> -extra_params = -cpu host,+vmx -append "-exit_monitor_from_l2_test -ept_access* -vmx_smp* -vmx_vmcs_shadow_test"
> +extra_params = -cpu host,+vmx -append "-exit_monitor_from_l2_test -ept_access* -vmx_smp* -vmx_vmcs_shadow_test -atomic_switch_overflow_msrs_test"
> arch = x86_64
> groups = vmx
>
> diff --git a/x86/vmx.c b/x86/vmx.c
> index 6079420db33a..7313c78f15c2 100644
> --- a/x86/vmx.c
> +++ b/x86/vmx.c
> @@ -1820,7 +1820,7 @@ static void __enter_guest(u8 abort_flag, struct vmentry_failure *failure)
> abort();
> }
>
> - if (!failure->early) {
> + if (!failure->early && !(vmcs_read(EXI_REASON) & VMX_ENTRY_FAILURE)) {
> launched = 1;
> check_for_guest_termination();
> }
> diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
> index f035f24a771a..fb665f38b1e5 100644
> --- a/x86/vmx_tests.c
> +++ b/x86/vmx_tests.c
> @@ -8570,6 +8570,134 @@ static int invalid_msr_entry_failure(struct vmentry_failure *failure)
> return VMX_TEST_VMEXIT;
> }
>
> +/*
> + * The max number of MSRs in an atomic switch MSR list is:
> + * (111B + 1) * 512 = 4096
> + *
> + * Each list entry consumes:
> + * 4-byte MSR index + 4 bytes reserved + 8-byte data = 16 bytes
> + *
> + * Allocate 128 kB to cover max_msr_list_size (i.e., 64 kB) and then some.
> + */
> +static const u32 msr_list_page_order = 5;
> +
> +static void atomic_switch_msr_limit_test_guest(void)
> +{
> + vmcall();
> +}
> +
> +static void populate_msr_list(struct vmx_msr_entry *msr_list,
> + size_t byte_capacity, int count)
> +{
> + int i;
> +
> + for (i = 0; i < count; i++) {
> + msr_list[i].index = MSR_IA32_TSC;
> + msr_list[i].reserved = 0;
> + msr_list[i].value = 0x1234567890abcdef;
> + }
> +
> + memset(msr_list + count, 0xff,
> + byte_capacity - count * sizeof(*msr_list));
> +}
> +
> +static int max_msr_list_size(void)
> +{
> + u32 vmx_misc = rdmsr(MSR_IA32_VMX_MISC);
> + u32 factor = ((vmx_misc & GENMASK(27, 25)) >> 25) + 1;
> +
> + return factor * 512;
> +}
> +
> +static void atomic_switch_msrs_test(int count)
> +{
> + struct vmx_msr_entry *vm_enter_load;
> + struct vmx_msr_entry *vm_exit_load;
> + struct vmx_msr_entry *vm_exit_store;
> + int max_allowed = max_msr_list_size();
> + int byte_capacity = 1ul << (msr_list_page_order + PAGE_SHIFT);
> + /* Exceeding the max MSR list size at exit trigers KVM to abort. */
> + int exit_count = count > max_allowed ? max_allowed : count;
> + int cleanup_count = count > max_allowed ? 2 : 1;
> + int i;
> +
> + /*
> + * Check for the IA32_TSC MSR,
> + * available with the "TSC flag" and used to populate the MSR lists.
> + */
> + if (!(cpuid(1).d & (1 << 4))) {
> + report_skip(__func__);
> + return;
> + }
> +
> + /* Set L2 guest. */
> + test_set_guest(atomic_switch_msr_limit_test_guest);
> +
> + /* Setup atomic MSR switch lists. */
> + vm_enter_load = alloc_pages(msr_list_page_order);
> + vm_exit_load = alloc_pages(msr_list_page_order);
> + vm_exit_store = alloc_pages(msr_list_page_order);
> +
> + vmcs_write(ENTER_MSR_LD_ADDR, (u64)vm_enter_load);
> + vmcs_write(EXIT_MSR_LD_ADDR, (u64)vm_exit_load);
> + vmcs_write(EXIT_MSR_ST_ADDR, (u64)vm_exit_store);
> +
> + /*
> + * VM-Enter should succeed up to the max number of MSRs per list, and
> + * should not consume junk beyond the last entry.
> + */
> + populate_msr_list(vm_enter_load, byte_capacity, count);
> + populate_msr_list(vm_exit_load, byte_capacity, exit_count);
> + populate_msr_list(vm_exit_store, byte_capacity, exit_count);
> +
> + vmcs_write(ENT_MSR_LD_CNT, count);
> + vmcs_write(EXI_MSR_LD_CNT, exit_count);
> + vmcs_write(EXI_MSR_ST_CNT, exit_count);
> +
> + if (count <= max_allowed) {
> + enter_guest();
> + assert_exit_reason(VMX_VMCALL);
> + skip_exit_vmcall();
> + } else {
> + u32 exit_reason;
> + u32 exit_reason_want;
> + u32 exit_qual;
> +
> + enter_guest_with_invalid_guest_state();
> +
> + exit_reason = vmcs_read(EXI_REASON);
> + exit_reason_want = VMX_FAIL_MSR | VMX_ENTRY_FAILURE;
> + report("exit_reason, %u, is %u.",
> + exit_reason == exit_reason_want, exit_reason,
> + exit_reason_want);
> +
> + exit_qual = vmcs_read(EXI_QUALIFICATION);
> + report("exit_qual, %u, is %u.", exit_qual == max_allowed + 1,
> + exit_qual, max_allowed + 1);
> + }
> +
> + /* Cleanup. */
> + vmcs_write(ENT_MSR_LD_CNT, 0);
> + vmcs_write(EXI_MSR_LD_CNT, 0);
> + vmcs_write(EXI_MSR_ST_CNT, 0);
> + for (i = 0; i < cleanup_count; i++) {
> + enter_guest();
> + skip_exit_vmcall();
> + }
> + free_pages_by_order(vm_enter_load, msr_list_page_order);
> + free_pages_by_order(vm_exit_load, msr_list_page_order);
> + free_pages_by_order(vm_exit_store, msr_list_page_order);
> +}
> +
> +static void atomic_switch_max_msrs_test(void)
> +{
> + atomic_switch_msrs_test(max_msr_list_size());
> +}
> +
> +static void atomic_switch_overflow_msrs_test(void)
> +{
> + atomic_switch_msrs_test(max_msr_list_size() + 1);
> +}
>
> #define TEST(name) { #name, .v2 = name }
>
> @@ -8660,5 +8788,8 @@ struct vmx_test vmx_tests[] = {
> TEST(ept_access_test_paddr_read_execute_ad_enabled),
> TEST(ept_access_test_paddr_not_present_page_fault),
> TEST(ept_access_test_force_2m_page),
> + /* Atomic MSR switch tests. */
> + TEST(atomic_switch_max_msrs_test),
> + TEST(atomic_switch_overflow_msrs_test),
> { NULL, NULL, NULL, NULL, NULL, {0} },
> };
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [kvm-unit-tests PATCH v2] x86: nvmx: test max atomic switch MSRs
2019-09-16 19:06 ` Krish Sadhukhan
@ 2019-09-16 21:11 ` Marc Orr
2019-09-17 18:59 ` Marc Orr
0 siblings, 1 reply; 4+ messages in thread
From: Marc Orr @ 2019-09-16 21:11 UTC (permalink / raw)
To: Krish Sadhukhan; +Cc: kvm, Jim Mattson, Peter Shier, Sean Christopherson
> > v1 -> v2
> > * Replaced 2M page allocations with 128 kB allocations.
> > * Broadly, updated test to follow Sean's draft:
> > * Got rid of loop + individual test cases. Instead combined all test cases.
> > * Got rid of configure_atomic_switch_msr_limit_test().
> > * Updated cleanup code to free memory. I added a new helper,
> > free_pages_by_order() to help here.
> > * Changed virt_to_phys() to explicit u64 cast.
> > * Renamed original test case from atomic_switch_msr_limit_test() to
> > atomic_switch_max_msrs_test(). Added opt-in
> > atomic_switch_overflow_msrs_test() test case to test failure code path
> > during VM-entry.
> > * Fixed a bug in transitioning VMX launched state when the first
> > VM-entry fails.
>
> Can we move this bug-fix to a separate patch so that it can be
> identified easily when searching in git history ?
SGTM. I'll wait to see if there are any more comments before splitting this out.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [kvm-unit-tests PATCH v2] x86: nvmx: test max atomic switch MSRs
2019-09-16 21:11 ` Marc Orr
@ 2019-09-17 18:59 ` Marc Orr
0 siblings, 0 replies; 4+ messages in thread
From: Marc Orr @ 2019-09-17 18:59 UTC (permalink / raw)
To: Krish Sadhukhan; +Cc: kvm, Jim Mattson, Peter Shier, Sean Christopherson
> > > v1 -> v2
> > > * Replaced 2M page allocations with 128 kB allocations.
> > > * Broadly, updated test to follow Sean's draft:
> > > * Got rid of loop + individual test cases. Instead combined all test cases.
> > > * Got rid of configure_atomic_switch_msr_limit_test().
> > > * Updated cleanup code to free memory. I added a new helper,
> > > free_pages_by_order() to help here.
> > > * Changed virt_to_phys() to explicit u64 cast.
> > > * Renamed original test case from atomic_switch_msr_limit_test() to
> > > atomic_switch_max_msrs_test(). Added opt-in
> > > atomic_switch_overflow_msrs_test() test case to test failure code path
> > > during VM-entry.
> > > * Fixed a bug in transitioning VMX launched state when the first
> > > VM-entry fails.
> >
> > Can we move this bug-fix to a separate patch so that it can be
> > identified easily when searching in git history ?
>
> SGTM. I'll wait to see if there are any more comments before splitting this out.
Done.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2019-09-14 0:49 [kvm-unit-tests PATCH v2] x86: nvmx: test max atomic switch MSRs Marc Orr
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2019-09-16 21:11 ` Marc Orr
2019-09-17 18:59 ` Marc Orr
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