From 37f0e8fe6b10ee2ab52576caa721ee1282de74a6 Mon Sep 17 00:00:00 2001 From: Junaid Shahid Date: Tue, 6 Dec 2016 16:46:15 -0800 Subject: kvm: x86: mmu: Do not use bit 63 for tracking special SPTEs MMIO SPTEs currently set both bits 62 and 63 to distinguish them as special PTEs. However, bit 63 is used as the SVE bit in Intel EPT PTEs. The SVE bit is ignored for misconfigured PTEs but not necessarily for not-Present PTEs. Since MMIO SPTEs use an EPT misconfiguration, so using bit 63 for them is acceptable. However, the upcoming fast access tracking feature adds another type of special tracking PTE, which uses not-Present PTEs and hence should not set bit 63. In order to use common bits to distinguish both type of special PTEs, we now use only bit 62 as the special bit. Signed-off-by: Junaid Shahid Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/x86/kvm/vmx.c') diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 81159a3878f4..6f53dedd9b96 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5236,10 +5236,10 @@ static void ept_set_mmio_spte_mask(void) /* * EPT Misconfigurations can be generated if the value of bits 2:0 * of an EPT paging-structure entry is 110b (write/execute). - * Also, magic bits (0x3ull << 62) is set to quickly identify mmio - * spte. + * Also, special bit (62) is set to quickly identify mmio spte. */ - kvm_mmu_set_mmio_spte_mask((0x3ull << 62) | 0x6ull); + kvm_mmu_set_mmio_spte_mask(SPTE_SPECIAL_MASK | + VMX_EPT_MISCONFIG_WX_VALUE); } #define VMX_XSS_EXIT_BITMAP 0 -- cgit