Add coverage to x86's set_sregs_test to verify KVM rejects vendor-agnostic
illegal CR0 values, i.e. CR0 values whose legality doesn't depend on the
current VMX mode. KVM historically has neglected to reject bad CR0s from
userspace, i.e. would happily accept a completely bogus CR0 via
KVM_SET_SREGS{2}.
Punt VMX specific subtests to future work, as they would require quite a
bit more effort, and KVM gets coverage for CR0 checks in general through
other means, e.g. KVM-Unit-Tests.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
.../selftests/kvm/x86_64/set_sregs_test.c | 70 +++++++++++--------
1 file changed, 39 insertions(+), 31 deletions(-)
diff --git a/tools/testing/selftests/kvm/x86_64/set_sregs_test.c b/tools/testing/selftests/kvm/x86_64/set_sregs_test.c
index a284fcef6ed7..3610981d9162 100644
--- a/tools/testing/selftests/kvm/x86_64/set_sregs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/set_sregs_test.c
@@ -22,26 +22,25 @@
#include "kvm_util.h"
#include "processor.h"
-static void test_cr4_feature_bit(struct kvm_vcpu *vcpu, struct kvm_sregs *orig,
- uint64_t feature_bit)
-{
- struct kvm_sregs sregs;
- int rc;
-
- /* Skip the sub-test, the feature is supported. */
- if (orig->cr4 & feature_bit)
- return;
-
- memcpy(&sregs, orig, sizeof(sregs));
- sregs.cr4 |= feature_bit;
-
- rc = _vcpu_sregs_set(vcpu, &sregs);
- TEST_ASSERT(rc, "KVM allowed unsupported CR4 bit (0x%lx)", feature_bit);
-
- /* Sanity check that KVM didn't change anything. */
- vcpu_sregs_get(vcpu, &sregs);
- TEST_ASSERT(!memcmp(&sregs, orig, sizeof(sregs)), "KVM modified sregs");
-}
+#define TEST_INVALID_CR_BIT(vcpu, cr, orig, bit) \
+do { \
+ struct kvm_sregs new; \
+ int rc; \
+ \
+ /* Skip the sub-test, the feature/bit is supported. */ \
+ if (orig.cr & bit) \
+ break; \
+ \
+ memcpy(&new, &orig, sizeof(sregs)); \
+ new.cr |= bit; \
+ \
+ rc = _vcpu_sregs_set(vcpu, &new); \
+ TEST_ASSERT(rc, "KVM allowed invalid " #cr " bit (0x%lx)", bit); \
+ \
+ /* Sanity check that KVM didn't change anything. */ \
+ vcpu_sregs_get(vcpu, &new); \
+ TEST_ASSERT(!memcmp(&new, &orig, sizeof(new)), "KVM modified sregs"); \
+} while (0)
static uint64_t calc_supported_cr4_feature_bits(void)
{
@@ -80,7 +79,7 @@ int main(int argc, char *argv[])
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
uint64_t cr4;
- int rc;
+ int rc, i;
/*
* Create a dummy VM, specifically to avoid doing KVM_SET_CPUID2, and
@@ -92,6 +91,7 @@ int main(int argc, char *argv[])
vcpu_sregs_get(vcpu, &sregs);
+ sregs.cr0 = 0;
sregs.cr4 |= calc_supported_cr4_feature_bits();
cr4 = sregs.cr4;
@@ -103,16 +103,24 @@ int main(int argc, char *argv[])
sregs.cr4, cr4);
/* Verify all unsupported features are rejected by KVM. */
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_UMIP);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_LA57);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_VMXE);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_SMXE);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_FSGSBASE);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_PCIDE);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_OSXSAVE);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_SMEP);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_SMAP);
- test_cr4_feature_bit(vcpu, &sregs, X86_CR4_PKE);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_UMIP);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_LA57);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_VMXE);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMXE);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_FSGSBASE);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_PCIDE);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_OSXSAVE);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMEP);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_SMAP);
+ TEST_INVALID_CR_BIT(vcpu, cr4, sregs, X86_CR4_PKE);
+
+ for (i = 32; i < 64; i++)
+ TEST_INVALID_CR_BIT(vcpu, cr0, sregs, BIT(i));
+
+ /* NW without CD is illegal, as is PG without PE. */
+ TEST_INVALID_CR_BIT(vcpu, cr0, sregs, X86_CR0_NW);
+ TEST_INVALID_CR_BIT(vcpu, cr0, sregs, X86_CR0_PG);
+
kvm_vm_free(vm);
/* Create a "real" VM and verify APIC_BASE can be set. */
--
2.41.0.162.gfafddb0af9-goog
