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KVM: selftests: x86: Prioritize getting max_gfn from GuestPhysBits

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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>
This commit is contained in:
Tao Su 2024-05-13 09:40:03 +08:00 committed by Sean Christopherson
parent d21b3c60d6
commit 980b8bc019
2 changed files with 14 additions and 2 deletions
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1
tools/testing/selftests/kvm/include/x86_64/processor.h
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@ -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)

15
tools/testing/selftests/kvm/lib/x86_64/processor.c
View File

@ -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)