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@xxxxxxxxx> Signed-off-by: Tao Su <tao1.su@xxxxxxxxxxxxxxx> Tested-by: Yi Lai <yi1.lai@xxxxxxxxx> Reviewed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx> --- This patch is based on https://github.com/kvm-x86/linux/commit/b628cb523c65 Changelog: v2 -> v3: - Drop kvm_cpu_has_p(X86_PROPERTY_MAX_GUEST_PHY_ADDR) check - Change max_bits to guest_pa_bits - Add Yi Lai's Reported-by and Xiaoyao's Reviewed-by v1 -> v2: - Only adjust vm->max_gfn in vm_compute_max_gfn() - Add Yi Lai's Tested-by v1: https://lore.kernel.org/all/20240508064205.15301-1-tao1.su@xxxxxxxxxxxxxxx/ --- tools/testing/selftests/kvm/include/x86_64/processor.h | 1 + tools/testing/selftests/kvm/lib/x86_64/processor.c | 9 +++++++-- 2 files changed, 8 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 81ce37ec407d..ff99f66d81a0 100644 --- a/tools/testing/selftests/kvm/include/x86_64/processor.h +++ b/tools/testing/selftests/kvm/include/x86_64/processor.h @@ -282,6 +282,7 @@ 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_MAX_GUEST_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 74a4c736c9ae..9458b36a30a8 100644 --- a/tools/testing/selftests/kvm/lib/x86_64/processor.c +++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c @@ -1293,10 +1293,15 @@ const struct kvm_cpuid2 *vcpu_get_supported_hv_cpuid(struct kvm_vcpu *vcpu) 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; + unsigned long ht_gfn, max_gfn, max_pfn, guest_pa_bits; uint8_t maxphyaddr; - max_gfn = (1ULL << (vm->pa_bits - vm->page_shift)) - 1; + guest_pa_bits = kvm_cpu_property(X86_PROPERTY_MAX_GUEST_PHY_ADDR); + + if (!guest_pa_bits) + guest_pa_bits = vm->pa_bits; + + max_gfn = (1ULL << (guest_pa_bits - vm->page_shift)) - 1; /* Avoid reserved HyperTransport region on AMD processors. */ if (!host_cpu_is_amd) base-commit: a38297e3fb012ddfa7ce0321a7e5a8daeb1872b6 -- 2.34.1
