| Message ID | 1408504651-7341-1-git-send-email-wanpeng.li@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Il 20/08/2014 05:17, Wanpeng Li ha scritto: > + else if (spte & (1ULL << 7)) You have to check level == 1 specifically here, or add... > + /* > + * 1GB/2MB page, bits 29:12 or 20:12 reserved respectively, > + * level == 1 if the hypervisor is using the ignored bit 7. > + */ > + mask |= (PAGE_SIZE << ((level - 1) * 9)) - PAGE_SIZE; > + else ... "if (level > 1)" here. Otherwise, you're marking bits 6:3 as reserved for 4K pages. This should cause a WARN, because KVM puts 0110 in those bits: ret = (MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT) | VMX_EPT_IPAT_BIT; (in vmx_get_mt_mask: writeback memory, ignore PAT memory type from the guest's page tables) How are you testing this patch? Paolo > + /* bits 6:3 reserved */ > + mask |= 0x78; -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Aug 20, 2014 at 08:51:38AM +0200, Paolo Bonzini wrote: >Il 20/08/2014 05:17, Wanpeng Li ha scritto: >> + else if (spte & (1ULL << 7)) > >You have to check level == 1 specifically here, or add... > >> + /* >> + * 1GB/2MB page, bits 29:12 or 20:12 reserved respectively, >> + * level == 1 if the hypervisor is using the ignored bit 7. >> + */ >> + mask |= (PAGE_SIZE << ((level - 1) * 9)) - PAGE_SIZE; >> + else > >... "if (level > 1)" here. > >Otherwise, you're marking bits 6:3 as reserved for 4K pages. This >should cause a WARN, because KVM puts 0110 in those bits: > > ret = (MTRR_TYPE_WRBACK << VMX_EPT_MT_EPTE_SHIFT) > | VMX_EPT_IPAT_BIT; > >(in vmx_get_mt_mask: writeback memory, ignore PAT memory type from the >guest's page tables) > Got it. Regards, Wanpeng Li >How are you testing this patch? > >Paolo > >> + /* bits 6:3 reserved */ >> + mask |= 0x78; -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index cad37d5..3218359 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -5521,17 +5521,18 @@ 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) + if (level == 4) /* bits 7:3 reserved */ mask |= 0xf8; - else if (level == 2) { - if (spte & (1ULL << 7)) - /* 2MB ref, bits 20:12 reserved */ - mask |= 0x1ff000; - else - /* bits 6:3 reserved */ - mask |= 0x78; - } + else if (spte & (1ULL << 7)) + /* + * 1GB/2MB page, bits 29:12 or 20:12 reserved respectively, + * level == 1 if the hypervisor is using the ignored bit 7. + */ + mask |= (PAGE_SIZE << ((level - 1) * 9)) - PAGE_SIZE; + else + /* bits 6:3 reserved */ + mask |= 0x78; return mask; } @@ -5561,7 +5562,8 @@ static void ept_misconfig_inspect_spte(struct kvm_vcpu *vcpu, u64 spte, WARN_ON(1); } - if (level == 1 || (level == 2 && (spte & (1ULL << 7)))) { + /* bits 5:3 are _not_ reserved for large page or leaf page */ + if ((rsvd_bits & 0x38) == 0) { u64 ept_mem_type = (spte & 0x38) >> 3; if (ept_mem_type == 2 || ept_mem_type == 3 ||
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> --- v2 -> v3: * return 0xf8 for level == 4 * check spte & (1ULL << 7) if level == 1 * (rsvd_mask & 0x38) == 0 for large page or leaf page v1 -> v2: * same "if" statement cover both 2MB and 1GB pages * return 0xf8 for level == 4 * get the level by checking the return value of ept_rsvd_mask arch/x86/kvm/vmx.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-)