From 4c26b4cd6ff6c3f7534f2aea9615a561c372ed05 Mon Sep 17 00:00:00 2001 From: Sheng Yang <sheng@linux.intel.com> Date: Thu, 2 Apr 2009 10:28:37 +0800 Subject: KVM: MMU: Discard reserved bits checking on PDE bit 7-8 1. It's related to a Linux kernel bug which fixed by Ingo on 07a66d7c53a538e1a9759954a82bb6c07365eff9. The original code exists for quite a long time, and it would convert a PDE for large page into a normal PDE. But it fail to fit normal PDE well. With the code before Ingo's fix, the kernel would fall reserved bit checking with bit 8 - the remaining global bit of PTE. So the kernel would receive a double-fault. 2. After discussion, we decide to discard PDE bit 7-8 reserved checking for now. For this marked as reserved in SDM, but didn't checked by the processor in fact... Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com> --- arch/x86/kvm/mmu.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index da3ad3cf314..b582adde683 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2194,7 +2194,7 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, int level) rsvd_bits(maxphyaddr, 63) | rsvd_bits(7, 8) | rsvd_bits(1, 2); /* PDPTE */ context->rsvd_bits_mask[0][1] = exb_bit_rsvd | - rsvd_bits(maxphyaddr, 62); /* PDE */ + rsvd_bits(maxphyaddr, 62); /* PDE */ context->rsvd_bits_mask[0][0] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 62); /* PTE */ context->rsvd_bits_mask[1][1] = exb_bit_rsvd | @@ -2208,13 +2208,14 @@ static void reset_rsvds_bits_mask(struct kvm_vcpu *vcpu, int level) context->rsvd_bits_mask[0][2] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8); context->rsvd_bits_mask[0][1] = exb_bit_rsvd | - rsvd_bits(maxphyaddr, 51) | rsvd_bits(7, 8); + rsvd_bits(maxphyaddr, 51); context->rsvd_bits_mask[0][0] = exb_bit_rsvd | rsvd_bits(maxphyaddr, 51); context->rsvd_bits_mask[1][3] = context->rsvd_bits_mask[0][3]; context->rsvd_bits_mask[1][2] = context->rsvd_bits_mask[0][2]; context->rsvd_bits_mask[1][1] = exb_bit_rsvd | - rsvd_bits(maxphyaddr, 51) | rsvd_bits(13, 20); + rsvd_bits(maxphyaddr, 51) | + rsvd_bits(13, 20); /* large page */ context->rsvd_bits_mask[1][0] = ~0ull; break; } -- cgit v1.2.3-70-g09d2