From: Paolo Bonzini Date: Wed, 11 Jun 2025 00:10:18 +0000 (-0400) Subject: KVM: x86/mmu: Embed direct bits into gpa for KVM_PRE_FAULT_MEMORY X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=aa2024c01a9afba6728b362626f868811ca872ee;p=linux-block.git KVM: x86/mmu: Embed direct bits into gpa for KVM_PRE_FAULT_MEMORY Bug[*] reported for TDX case when enabling KVM_PRE_FAULT_MEMORY in QEMU. It turns out that @gpa passed to kvm_mmu_do_page_fault() doesn't have shared bit set when the memory attribute of it is shared, and it leads to wrong root in tdp_mmu_get_root_for_fault(). Fix it by embedding the direct bits in the gpa that is passed to kvm_tdp_map_page(), when the memory of the gpa is not private. [*] https://lore.kernel.org/qemu-devel/4a757796-11c2-47f1-ae0d-335626e818fd@intel.com/ Reported-by: Xiaoyao Li Closes: https://lore.kernel.org/qemu-devel/4a757796-11c2-47f1-ae0d-335626e818fd@intel.com/ Signed-off-by: Paolo Bonzini Signed-off-by: Xiaoyao Li Message-ID: <20250611001018.2179964-1-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini --- diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index cbc84c6abc2e..a4040578b537 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4896,6 +4896,7 @@ long kvm_arch_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu, { u64 error_code = PFERR_GUEST_FINAL_MASK; u8 level = PG_LEVEL_4K; + u64 direct_bits; u64 end; int r; @@ -4910,15 +4911,18 @@ long kvm_arch_vcpu_pre_fault_memory(struct kvm_vcpu *vcpu, if (r) return r; + direct_bits = 0; if (kvm_arch_has_private_mem(vcpu->kvm) && kvm_mem_is_private(vcpu->kvm, gpa_to_gfn(range->gpa))) error_code |= PFERR_PRIVATE_ACCESS; + else + direct_bits = gfn_to_gpa(kvm_gfn_direct_bits(vcpu->kvm)); /* * Shadow paging uses GVA for kvm page fault, so restrict to * two-dimensional paging. */ - r = kvm_tdp_map_page(vcpu, range->gpa, error_code, &level); + r = kvm_tdp_map_page(vcpu, range->gpa | direct_bits, error_code, &level); if (r < 0) return r;