From 458e98746fa852d744d34b5a8d0b1673959efc2f Mon Sep 17 00:00:00 2001 From: David Matlack Date: Thu, 29 Sep 2022 11:12:07 -0700 Subject: [PATCH] KVM: selftests: Fix nx_huge_pages_test on TDP-disabled hosts Map the test's huge page region with 2MiB virtual mappings when TDP is disabled so that KVM can shadow the region with huge pages. This fixes nx_huge_pages_test on hosts where TDP hardware support is disabled. Purposely do not skip this test on TDP-disabled hosts. While we don't care about NX Huge Pages on TDP-disabled hosts from a security perspective, KVM does support it, and so we should test it. For TDP-enabled hosts, continue mapping the region with 4KiB pages to ensure that KVM can map it with huge pages irrespective of the guest mappings. Fixes: 8448ec5993be ("KVM: selftests: Add NX huge pages test") Signed-off-by: David Matlack Message-Id: <20220929181207.2281449-4-dmatlack@google.com> Signed-off-by: Paolo Bonzini --- .../selftests/kvm/include/x86_64/processor.h | 4 ++++ tools/testing/selftests/kvm/lib/x86_64/processor.c | 27 ++++++++++++++++++++++ .../selftests/kvm/x86_64/nx_huge_pages_test.c | 19 +++++++++++++-- 3 files changed, 48 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h index 0cbc71b..e8ca0d8 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -825,6 +825,8 @@ static inline uint8_t wrmsr_safe(uint32_t msr, uint64_t val) return kvm_asm_safe("wrmsr", "a"(val & -1u), "d"(val >> 32), "c"(msr)); } +bool kvm_is_tdp_enabled(void); + uint64_t vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu, uint64_t vaddr); void vm_set_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu, @@ -855,6 +857,8 @@ enum pg_level { #define PG_SIZE_1G PG_LEVEL_SIZE(PG_LEVEL_1G) void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level); +void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, + uint64_t nr_bytes, int level); /* * Basic CPU control in CR0 diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c index fab0f52..39c4409 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -111,6 +111,14 @@ static void sregs_dump(FILE *stream, struct kvm_sregs *sregs, uint8_t indent) } } +bool kvm_is_tdp_enabled(void) +{ + if (is_intel_cpu()) + return get_kvm_intel_param_bool("ept"); + else + return get_kvm_amd_param_bool("npt"); +} + void virt_arch_pgd_alloc(struct kvm_vm *vm) { TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use " @@ -214,6 +222,25 @@ void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr) __virt_pg_map(vm, vaddr, paddr, PG_LEVEL_4K); } +void virt_map_level(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, + uint64_t nr_bytes, int level) +{ + uint64_t pg_size = PG_LEVEL_SIZE(level); + uint64_t nr_pages = nr_bytes / pg_size; + int i; + + TEST_ASSERT(nr_bytes % pg_size == 0, + "Region size not aligned: nr_bytes: 0x%lx, page size: 0x%lx", + nr_bytes, pg_size); + + for (i = 0; i < nr_pages; i++) { + __virt_pg_map(vm, vaddr, paddr, level); + + vaddr += pg_size; + paddr += pg_size; + } +} + static uint64_t *_vm_get_page_table_entry(struct kvm_vm *vm, struct kvm_vcpu *vcpu, uint64_t vaddr) diff --git a/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c index cc64217..8c1181a 100644 --- a/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c +++ b/tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c @@ -112,6 +112,7 @@ void run_test(int reclaim_period_ms, bool disable_nx_huge_pages, { struct kvm_vcpu *vcpu; struct kvm_vm *vm; + uint64_t nr_bytes; void *hva; int r; @@ -141,10 +142,24 @@ void run_test(int reclaim_period_ms, bool disable_nx_huge_pages, HPAGE_GPA, HPAGE_SLOT, HPAGE_SLOT_NPAGES, 0); - virt_map(vm, HPAGE_GVA, HPAGE_GPA, HPAGE_SLOT_NPAGES); + nr_bytes = HPAGE_SLOT_NPAGES * vm->page_size; + + /* + * Ensure that KVM can map HPAGE_SLOT with huge pages by mapping the + * region into the guest with 2MiB pages whenever TDP is disabled (i.e. + * whenever KVM is shadowing the guest page tables). + * + * When TDP is enabled, KVM should be able to map HPAGE_SLOT with huge + * pages irrespective of the guest page size, so map with 4KiB pages + * to test that that is the case. + */ + if (kvm_is_tdp_enabled()) + virt_map_level(vm, HPAGE_GVA, HPAGE_GPA, nr_bytes, PG_LEVEL_4K); + else + virt_map_level(vm, HPAGE_GVA, HPAGE_GPA, nr_bytes, PG_LEVEL_2M); hva = addr_gpa2hva(vm, HPAGE_GPA); - memset(hva, RETURN_OPCODE, HPAGE_SLOT_NPAGES * PAGE_SIZE); + memset(hva, RETURN_OPCODE, nr_bytes); check_2m_page_count(vm, 0); check_split_count(vm, 0); -- 2.7.4