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Subject[PATCH 1/5] KVM: vmx: fix ept reserved bits for 1-GByte page
Date
EPT misconfig handler in kvm will check which reason lead to EPT 
misconfiguration after vmexit. One of the reasons is that an EPT
paging-structure entry is configured with settings reserved for
future functionality. However, the handler can't identify if
paging-structure entry of reserved bits for 1-GByte page are
configured, since PDPTE which point to 1-GByte page will reserve
bits 29:12 instead of bits 7:3 which are reserved for PDPTE that
references an EPT Page Directory. This patch fix it by reserve
bits 29:12 for 1-GByte page.

Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
---
arch/x86/kvm/vmx.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index bfe11cf..71cbee5 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5521,9 +5521,14 @@ static u64 ept_rsvd_mask(u64 spte, int level)
for (i = 51; i > boot_cpu_data.x86_phys_bits; i--)
mask |= (1ULL << i);

- if (level > 2)
- /* bits 7:3 reserved */
- mask |= 0xf8;
+ if (level > 2) {
+ if (spte & (1 << 7))
+ /* 1GB ref, bits 29:12 */
+ mask |= 0x3ffff000;
+ else
+ /* bits 7:3 reserved */
+ mask |= 0xf8;
+ }
else if (level == 2) {
if (spte & (1ULL << 7))
/* 2MB ref, bits 20:12 reserved */
@@ -5561,7 +5566,8 @@ static void ept_misconfig_inspect_spte(struct kvm_vcpu *vcpu, u64 spte,
WARN_ON(1);
}

- if (level == 1 || (level == 2 && (spte & (1ULL << 7)))) {
+ if (level == 1 || ((level == 3 || level == 2)
+ && (spte & (1ULL << 7)))) {
u64 ept_mem_type = (spte & 0x38) >> 3;

if (ept_mem_type == 2 || ept_mem_type == 3 ||
--
1.9.1


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