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authorTao Su <tao1.su@linux.intel.com>2024-05-13 09:40:03 +0800
committerSean Christopherson <seanjc@google.com>2024-06-05 06:16:10 -0700
commit980b8bc01938c8bcc9742c1051f64b5f0ed178ac (patch)
tree0bf3dfac527077cb2f266b669c86250eebdad8ab
parentd21b3c60d6e3917f7388db6bcc455f01c99ee42b (diff)
KVM: selftests: x86: Prioritize getting max_gfn from GuestPhysBits
Use the max mappable GPA via GuestPhysBits advertised by KVM to calculate max_gfn. Currently some selftests (e.g. access_tracking_perf_test, dirty_log_test...) add RAM regions close to max_gfn, so guest may access GPA beyond its mappable range and cause infinite loop. Adjust max_gfn in vm_compute_max_gfn() since x86 selftests already overrides vm_compute_max_gfn() specifically to deal with goofy edge cases. Reported-by: Yi Lai <yi1.lai@intel.com> Signed-off-by: Tao Su <tao1.su@linux.intel.com> Tested-by: Yi Lai <yi1.lai@intel.com> Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com> Link: https://lore.kernel.org/r/20240513014003.104593-1-tao1.su@linux.intel.com [sean: tweak name, add comment and sanity check] Signed-off-by: Sean Christopherson <seanjc@google.com>
-rw-r--r--tools/testing/selftests/kvm/include/x86_64/processor.h1
-rw-r--r--tools/testing/selftests/kvm/lib/x86_64/processor.c15
2 files changed, 14 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 8eb57de0b587..c0c7c1fe93f9 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -277,6 +277,7 @@ struct kvm_x86_cpu_property {
#define X86_PROPERTY_MAX_EXT_LEAF KVM_X86_CPU_PROPERTY(0x80000000, 0, EAX, 0, 31)
#define X86_PROPERTY_MAX_PHY_ADDR KVM_X86_CPU_PROPERTY(0x80000008, 0, EAX, 0, 7)
#define X86_PROPERTY_MAX_VIRT_ADDR KVM_X86_CPU_PROPERTY(0x80000008, 0, EAX, 8, 15)
+#define X86_PROPERTY_GUEST_MAX_PHY_ADDR KVM_X86_CPU_PROPERTY(0x80000008, 0, EAX, 16, 23)
#define X86_PROPERTY_SEV_C_BIT KVM_X86_CPU_PROPERTY(0x8000001F, 0, EBX, 0, 5)
#define X86_PROPERTY_PHYS_ADDR_REDUCTION KVM_X86_CPU_PROPERTY(0x8000001F, 0, EBX, 6, 11)
diff --git a/tools/testing/selftests/kvm/lib/x86_64/processor.c b/tools/testing/selftests/kvm/lib/x86_64/processor.c
index c664e446136b..594b061aef52 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c
@@ -1247,9 +1247,20 @@ unsigned long vm_compute_max_gfn(struct kvm_vm *vm)
{
const unsigned long num_ht_pages = 12 << (30 - vm->page_shift); /* 12 GiB */
unsigned long ht_gfn, max_gfn, max_pfn;
- uint8_t maxphyaddr;
+ uint8_t maxphyaddr, guest_maxphyaddr;
- max_gfn = (1ULL << (vm->pa_bits - vm->page_shift)) - 1;
+ /*
+ * Use "guest MAXPHYADDR" from KVM if it's available. Guest MAXPHYADDR
+ * enumerates the max _mappable_ GPA, which can be less than the raw
+ * MAXPHYADDR, e.g. if MAXPHYADDR=52, KVM is using TDP, and the CPU
+ * doesn't support 5-level TDP.
+ */
+ guest_maxphyaddr = kvm_cpu_property(X86_PROPERTY_GUEST_MAX_PHY_ADDR);
+ guest_maxphyaddr = guest_maxphyaddr ?: vm->pa_bits;
+ TEST_ASSERT(guest_maxphyaddr <= vm->pa_bits,
+ "Guest MAXPHYADDR should never be greater than raw MAXPHYADDR");
+
+ max_gfn = (1ULL << (guest_maxphyaddr - vm->page_shift)) - 1;
/* Avoid reserved HyperTransport region on AMD processors. */
if (!host_cpu_is_amd)