On Mon, May 13, 2024 at 10:00:35AM +0800, Tao Su wrote: >On Mon, May 13, 2024 at 09:44:32AM +0800, Chao Gao wrote: >> On Fri, May 10, 2024 at 10:03:46AM +0800, Tao Su wrote: >> >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. >> > >> >Signed-off-by: Tao Su <tao1.su@xxxxxxxxxxxxxxx> >> >Tested-by: Yi Lai <yi1.lai@xxxxxxxxx> >> >--- >> >This patch is based on https://github.com/kvm-x86/linux/commit/b628cb523c65 >> > >> >Changelog: >> >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 | 10 ++++++++-- >> > 2 files changed, 9 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..aa9966ead543 100644 >> >--- a/tools/testing/selftests/kvm/lib/x86_64/processor.c >> >+++ b/tools/testing/selftests/kvm/lib/x86_64/processor.c >> >@@ -1293,10 +1293,16 @@ 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, max_bits = 0; >> >> nit: max_bits has only 8 bits. so max_bits should be uint8_t. > >Because vm->pa_bits is unsigned int, I'm worried that the compiler will >complain on stricter compilation, what do you think? @maxphyaddr (right below) is in the same situation. And if it was a problem for the compiler, casting vm->page_shift to uint8_t explicitly would be a better solution. > >> >> > uint8_t maxphyaddr; >> > >> >- max_gfn = (1ULL << (vm->pa_bits - vm->page_shift)) - 1; >> >+ if (kvm_cpu_has_p(X86_PROPERTY_MAX_GUEST_PHY_ADDR)) >> >+ max_bits = kvm_cpu_property(X86_PROPERTY_MAX_GUEST_PHY_ADDR); >> >+ >> >+ if (!max_bits) >> >+ max_bits = vm->pa_bits; >> >+ >> >+ max_gfn = (1ULL << (max_bits - vm->page_shift)) - 1; >> > >> > /* Avoid reserved HyperTransport region on AMD processors. */ >> > if (!host_cpu_is_amd) >> > >> >base-commit: 448b3fe5a0eab5b625a7e15c67c7972169e47ff8 >> >-- >> >2.34.1 >> >
