From 10f89f4323c4ff4cd5cbf2c2571ec408fa565794 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 29 Aug 2019 14:06:58 -0300 Subject: [PATCH] KVM: x86: SVM: Set EMULTYPE_NO_REEXECUTE for RSM emulation MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit BugLink: https://bugs.launchpad.net/bugs/1834522 Re-execution after an emulation decode failure is only intended to handle a case where two or vCPUs race to write a shadowed page, i.e. we should never re-execute an instruction as part of RSM emulation. Add a new helper, kvm_emulate_instruction_from_buffer(), to support emulating from a pre-defined buffer. This eliminates the last direct call to x86_emulate_instruction() outside of kvm_mmu_page_fault(), which means x86_emulate_instruction() can be unexported in a future patch. Fixes: 7607b7174405 ("KVM: SVM: install RSM intercept") Cc: Brijesh Singh Signed-off-by: Sean Christopherson Cc: stable@vger.kernel.org Signed-off-by: Radim Krčmář (cherry-picked from 35be0aded76b54a24dc8aa678a71bca22273e8d8) Signed-off-by: Rafael David Tinoco Acked-by: Kleber Souza Acked-by: Thadeu Lima de Souza Cascardo Signed-off-by: Khalid Elmously --- arch/x86/include/asm/kvm_host.h | 7 +++++++ arch/x86/kvm/svm.c | 4 ++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 11838996bd59..51d587825a59 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1190,6 +1190,13 @@ static inline int emulate_instruction(struct kvm_vcpu *vcpu, emulation_type | EMULTYPE_NO_REEXECUTE, NULL, 0); } +static inline int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu, + void *insn, int insn_len) +{ + return x86_emulate_instruction(vcpu, 0, EMULTYPE_NO_REEXECUTE, + insn, insn_len); +} + void kvm_enable_efer_bits(u64); bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer); int kvm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr); diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 77a98268df8a..779ae76c7a52 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -3461,8 +3461,8 @@ static int emulate_on_interception(struct vcpu_svm *svm) static int rsm_interception(struct vcpu_svm *svm) { - return x86_emulate_instruction(&svm->vcpu, 0, 0, - rsm_ins_bytes, 2) == EMULATE_DONE; + return kvm_emulate_instruction_from_buffer(&svm->vcpu, + rsm_ins_bytes, 2) == EMULATE_DONE; } static int rdpmc_interception(struct vcpu_svm *svm) -- 2.39.5