From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: [PATCH v4 64/75] x86/paravirt: Allow hypervisor specific VMMCALL handling under SEV-ES Date: Tue, 14 Jul 2020 14:09:06 +0200 Message-ID: <20200714120917.11253-65-joro@8bytes.org> References: <20200714120917.11253-1-joro@8bytes.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200714120917.11253-1-joro@8bytes.org> Sender: linux-kernel-owner@vger.kernel.org To: x86@kernel.org Cc: Joerg Roedel , Joerg Roedel , hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , Martin Radev , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org From: Joerg Roedel Add two new paravirt callbacks to provide hypervisor specific processor state in the GHCB and to copy state from the hypervisor back to the processor. Signed-off-by: Joerg Roedel --- arch/x86/include/asm/x86_init.h | 16 +++++++++++++++- arch/x86/kernel/sev-es.c | 12 ++++++++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h index 6807153c0410..0304e2931cd3 100644 --- a/arch/x86/include/asm/x86_init.h +++ b/arch/x86/include/asm/x86_init.h @@ -4,8 +4,10 @@ #include +struct ghcb; struct mpc_bus; struct mpc_cpu; +struct pt_regs; struct mpc_table; struct cpuinfo_x86; @@ -236,10 +238,22 @@ struct x86_legacy_features { /** * struct x86_hyper_runtime - x86 hypervisor specific runtime callbacks * - * @pin_vcpu: pin current vcpu to specified physical cpu (run rarely) + * @pin_vcpu: pin current vcpu to specified physical + * cpu (run rarely) + * @sev_es_hcall_prepare: Load additional hypervisor-specific + * state into the GHCB when doing a VMMCALL under + * SEV-ES. Called from the #VC exception handler. + * @sev_es_hcall_finish: Copies state from the GHCB back into the + * processor (or pt_regs). Also runs checks on the + * state returned from the hypervisor after a + * VMMCALL under SEV-ES. Needs to return 'false' + * if the checks fail. Called from the #VC + * exception handler. */ struct x86_hyper_runtime { void (*pin_vcpu)(int cpu); + void (*sev_es_hcall_prepare)(struct ghcb *ghcb, struct pt_regs *regs); + bool (*sev_es_hcall_finish)(struct ghcb *ghcb, struct pt_regs *regs); }; /** diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index b0f08d9669f1..76104c71fc85 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -903,6 +903,9 @@ static enum es_result vc_handle_vmmcall(struct ghcb *ghcb, ghcb_set_rax(ghcb, ctxt->regs->ax); ghcb_set_cpl(ghcb, user_mode(ctxt->regs) ? 3 : 0); + if (x86_platform.hyper.sev_es_hcall_prepare) + x86_platform.hyper.sev_es_hcall_prepare(ghcb, ctxt->regs); + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_VMMCALL, 0, 0); if (ret != ES_OK) return ret; @@ -912,6 +915,15 @@ static enum es_result vc_handle_vmmcall(struct ghcb *ghcb, ctxt->regs->ax = ghcb->save.rax; + /* + * Call sev_es_hcall_finish() after regs->ax is already set. + * This allows the hypervisor handler to overwrite it again if + * necessary. + */ + if (x86_platform.hyper.sev_es_hcall_finish && + !x86_platform.hyper.sev_es_hcall_finish(ghcb, ctxt->regs)) + return ES_VMM_ERROR; + return ES_OK; } -- 2.27.0