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Message-ID: <20240209222858.396696-3-seanjc@google.com>
Date: Fri, 9 Feb 2024 14:28:56 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
Yan Zhao <yan.y.zhao@...el.com>, Friedrich Weber <f.weber@...xmox.com>,
Kai Huang <kai.huang@...el.com>, Yuan Yao <yuan.yao@...ux.intel.com>,
Xu Yilun <yilun.xu@...ux.intel.com>, Yu Zhang <yu.c.zhang@...ux.intel.com>,
Chao Peng <chao.p.peng@...ux.intel.com>, Fuad Tabba <tabba@...gle.com>,
Michael Roth <michael.roth@....com>, Isaku Yamahata <isaku.yamahata@...el.com>,
David Matlack <dmatlack@...gle.com>
Subject: [PATCH v4 2/4] KVM: x86/mmu: Move private vs. shared check above slot
validity checks
Prioritize private vs. shared gfn attribute checks above slot validity
checks to ensure a consistent userspace ABI. E.g. as is, KVM will exit to
userspace if there is no memslot, but emulate accesses to the APIC access
page even if the attributes mismatch.
Fixes: 8dd2eee9d526 ("KVM: x86/mmu: Handle page fault for private memory")
Cc: Yu Zhang <yu.c.zhang@...ux.intel.com>
Cc: Chao Peng <chao.p.peng@...ux.intel.com>
Cc: Fuad Tabba <tabba@...gle.com>
Cc: Michael Roth <michael.roth@....com>
Cc: Isaku Yamahata <isaku.yamahata@...el.com>
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/kvm/mmu/mmu.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 166cef0c3ff4..50bfaa53f3f2 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4360,11 +4360,6 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
return RET_PF_EMULATE;
}
- if (fault->is_private != kvm_mem_is_private(vcpu->kvm, fault->gfn)) {
- kvm_mmu_prepare_memory_fault_exit(vcpu, fault);
- return -EFAULT;
- }
-
if (fault->is_private)
return kvm_faultin_pfn_private(vcpu, fault);
@@ -4403,6 +4398,11 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
struct kvm_memory_slot *slot = fault->slot;
int ret;
+ if (fault->is_private != kvm_mem_is_private(vcpu->kvm, fault->gfn)) {
+ kvm_mmu_prepare_memory_fault_exit(vcpu, fault);
+ return -EFAULT;
+ }
+
fault->mmu_seq = vcpu->kvm->mmu_invalidate_seq;
smp_rmb();
--
2.43.0.687.g38aa6559b0-goog
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