diff options
Diffstat (limited to 'meta-amd-bsp/recipes-kernel/linux/linux-yocto-4.14.71-e3000/0084-KVM-X86-Restart-the-guest-when-insn_len-is-zero-and-.patch')
| -rw-r--r-- | meta-amd-bsp/recipes-kernel/linux/linux-yocto-4.14.71-e3000/0084-KVM-X86-Restart-the-guest-when-insn_len-is-zero-and-.patch | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/meta-amd-bsp/recipes-kernel/linux/linux-yocto-4.14.71-e3000/0084-KVM-X86-Restart-the-guest-when-insn_len-is-zero-and-.patch b/meta-amd-bsp/recipes-kernel/linux/linux-yocto-4.14.71-e3000/0084-KVM-X86-Restart-the-guest-when-insn_len-is-zero-and-.patch new file mode 100644 index 00000000..984f10e2 --- /dev/null +++ b/meta-amd-bsp/recipes-kernel/linux/linux-yocto-4.14.71-e3000/0084-KVM-X86-Restart-the-guest-when-insn_len-is-zero-and-.patch @@ -0,0 +1,88 @@ +From cc62d922be657a89f3c8afbfd97f5cfc37a5a036 Mon Sep 17 00:00:00 2001 +From: Brijesh Singh <brijesh.singh@amd.com> +Date: Mon, 4 Dec 2017 10:57:40 -0600 +Subject: [PATCH 84/95] KVM: X86: Restart the guest when insn_len is zero and + SEV is enabled +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +On AMD platforms, under certain conditions insn_len may be zero on #NPF. +This can happen if a guest gets a page-fault on data access but the HW +table walker is not able to read the instruction page (e.g instruction +page is not present in memory). + +Typically, when insn_len is zero, x86_emulate_instruction() walks the +guest page table and fetches the instruction bytes from guest memory. +When SEV is enabled, the guest memory is encrypted with guest-specific +key hence hypervisor will not able to fetch the instruction bytes. +In those cases we simply restart the guest. + +I have encountered this issue when running kernbench inside the guest. + +Cc: Thomas Gleixner <tglx@linutronix.de> +Cc: Ingo Molnar <mingo@redhat.com> +Cc: "H. Peter Anvin" <hpa@zytor.com> +Cc: Paolo Bonzini <pbonzini@redhat.com> +Cc: "Radim Krčmář" <rkrcmar@redhat.com> +Cc: Joerg Roedel <joro@8bytes.org> +Cc: Borislav Petkov <bp@suse.de> +Cc: Tom Lendacky <thomas.lendacky@amd.com> +Cc: x86@kernel.org +Cc: kvm@vger.kernel.org +Cc: linux-kernel@vger.kernel.org +Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> +Signed-off-by: Sudheesh Mavila <sudheesh.mavila@amd.com> +--- + arch/x86/kvm/mmu.c | 10 ++++++++++ + arch/x86/kvm/svm.c | 6 ++++-- + 2 files changed, 14 insertions(+), 2 deletions(-) + +diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c +index 1408d79..fcab730 100644 +--- a/arch/x86/kvm/mmu.c ++++ b/arch/x86/kvm/mmu.c +@@ -4987,6 +4987,16 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code, + if (mmio_info_in_cache(vcpu, cr2, direct)) + emulation_type = 0; + emulate: ++ /* ++ * On AMD platforms, under certain conditions insn_len may be zero on #NPF. ++ * This can happen if a guest gets a page-fault on data access but the HW ++ * table walker is not able to read the instruction page (e.g instruction ++ * page is not present in memory). In those cases we simply restart the ++ * guest. ++ */ ++ if (unlikely(insn && !insn_len)) ++ return 1; ++ + er = x86_emulate_instruction(vcpu, cr2, emulation_type, insn, insn_len); + + switch (er) { +diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c +index 331b127..399ad5e 100755 +--- a/arch/x86/kvm/svm.c ++++ b/arch/x86/kvm/svm.c +@@ -2487,7 +2487,8 @@ static int pf_interception(struct vcpu_svm *svm) + u64 error_code = svm->vmcb->control.exit_info_1; + + return kvm_handle_page_fault(&svm->vcpu, error_code, fault_address, +- svm->vmcb->control.insn_bytes, ++ static_cpu_has(X86_FEATURE_DECODEASSISTS) ? ++ svm->vmcb->control.insn_bytes : NULL, + svm->vmcb->control.insn_len); + } + +@@ -2498,7 +2499,8 @@ static int npf_interception(struct vcpu_svm *svm) + + trace_kvm_page_fault(fault_address, error_code); + return kvm_mmu_page_fault(&svm->vcpu, fault_address, error_code, +- svm->vmcb->control.insn_bytes, ++ static_cpu_has(X86_FEATURE_DECODEASSISTS) ? ++ svm->vmcb->control.insn_bytes : NULL, + svm->vmcb->control.insn_len); + } + +-- +2.7.4 + |