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KVM: selftests: Fix nx_huge_pages_test on TDP-disabled hosts

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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: 8448ec5993 ("KVM: selftests: Add NX huge pages test")
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220929181207.2281449-4-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
David Matlack 2022-09-29 11:12:07 -07:00 committed by Paolo Bonzini
parent 4d2bd14319
commit 458e98746f
3 changed files with 48 additions and 2 deletions
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4
tools/testing/selftests/kvm/include/x86_64/processor.h
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@ -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

27
tools/testing/selftests/kvm/lib/x86_64/processor.c
View File

@ -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)

19
tools/testing/selftests/kvm/x86_64/nx_huge_pages_test.c
View File

@ -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);