From a512177ef3bb92dbec8a96fe337b11c126bf9c91 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 24 Jul 2017 18:54:38 +0200 Subject: [PATCH] KVM: x86: do mask out upper bits of PAE CR3 This reverts the change of commit f85c758dbee54cc3612a6e873ef7cecdb66ebee5, as the behavior it modified was intended. The VM is running in 32-bit PAE mode, and Table 4-7 of the Intel manual says: Table 4-7. Use of CR3 with PAE Paging Bit Position(s) Contents 4:0 Ignored 31:5 Physical address of the 32-Byte aligned page-directory-pointer table used for linear-address translation 63:32 Ignored (these bits exist only on processors supporting the Intel-64 architecture) To placate the static checker, write the mask explicitly as an unsigned long constant instead of using a 32-bit unsigned constant. Cc: Dan Carpenter Fixes: f85c758dbee54cc3612a6e873ef7cecdb66ebee5 Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 82a63c5..6c97c82 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -597,8 +597,8 @@ bool pdptrs_changed(struct kvm_vcpu *vcpu) (unsigned long *)&vcpu->arch.regs_avail)) return true; - gfn = (kvm_read_cr3(vcpu) & ~31ul) >> PAGE_SHIFT; - offset = (kvm_read_cr3(vcpu) & ~31ul) & (PAGE_SIZE - 1); + gfn = (kvm_read_cr3(vcpu) & 0xffffffe0ul) >> PAGE_SHIFT; + offset = (kvm_read_cr3(vcpu) & 0xffffffe0ul) & (PAGE_SIZE - 1); r = kvm_read_nested_guest_page(vcpu, gfn, pdpte, offset, sizeof(pdpte), PFERR_USER_MASK | PFERR_WRITE_MASK); if (r < 0) -- 2.7.4