| Message ID | 20190914004919.256530-1-marcorr@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [kvm-unit-tests,v2] x86: nvmx: test max atomic switch MSRs | expand |
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} }, > };
> > 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.
> > > 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.
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} }, };
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(-)