From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7ECC7C433E6 for ; Mon, 25 Jan 2021 20:09:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41BE42255F for ; Mon, 25 Jan 2021 20:09:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731780AbhAYUJE (ORCPT ); Mon, 25 Jan 2021 15:09:04 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:57191 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731422AbhAYUIA (ORCPT ); Mon, 25 Jan 2021 15:08:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611605193; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VjY+Q6oat1z43JuxPE0IZ3Kv3T5sx064JjJN1c5n1Bk=; b=Wkg1Pbd3AVI1cNVucys7d6pdRE6n+wbUQIx8nq1VzXm2ZRHe952xgwsvKthtXJXHAgoEtH oQHx1uIXchHjlIrt1jgz8JWJ19wSJ3vrTz91XiHEUQHU5BnZsYE/DKqqmpEVI8PfSlVneR V6R/US2sEaOplYy1M52/BJ/jDo6Hlyc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-499-FVduRbMZNhGBClCYTe9zjw-1; Mon, 25 Jan 2021 15:06:31 -0500 X-MC-Unique: FVduRbMZNhGBClCYTe9zjw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8B9E11005D44; Mon, 25 Jan 2021 20:06:28 +0000 (UTC) Received: from work-vm (ovpn-114-3.ams2.redhat.com [10.36.114.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3961677707; Mon, 25 Jan 2021 20:06:17 +0000 (UTC) Date: Mon, 25 Jan 2021 20:06:14 +0000 From: "Dr. David Alan Gilbert" To: Tom Lendacky Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Marcel Apfelbaum , Paolo Bonzini , Eduardo Habkost , Richard Henderson , Connor Kuehl , Brijesh Singh , Jiri Slaby , Marcelo Tosatti , "Michael S. Tsirkin" , Sean Christopherson , Peter Maydell , Aurelien Jarno , Jiaxun Yang , Aleksandar Rikalo , David Gibson , David Hildenbrand Subject: Re: [PATCH v5 4/6] sev/i386: Don't allow a system reset under an SEV-ES guest Message-ID: <20210125200614.GT2925@work-vm> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org * Tom Lendacky (thomas.lendacky@amd.com) wrote: > From: Tom Lendacky > > An SEV-ES guest does not allow register state to be altered once it has > been measured. When an SEV-ES guest issues a reboot command, Qemu will > reset the vCPU state and resume the guest. This will cause failures under > SEV-ES. Prevent that from occuring by introducing an arch-specific > callback that returns a boolean indicating whether vCPUs are resettable. > > Cc: Peter Maydell > Cc: Aurelien Jarno > Cc: Jiaxun Yang > Cc: Aleksandar Rikalo > Cc: David Gibson > Cc: David Hildenbrand > Signed-off-by: Tom Lendacky Thanks, that looks better than the earlier version. Needs checking by one of the kvm guys, but I think: Reviewed-by: Dr. David Alan Gilbert > --- > accel/kvm/kvm-all.c | 5 +++++ > include/sysemu/cpus.h | 2 ++ > include/sysemu/hw_accel.h | 5 +++++ > include/sysemu/kvm.h | 10 ++++++++++ > softmmu/cpus.c | 5 +++++ > softmmu/runstate.c | 7 +++++-- > target/arm/kvm.c | 5 +++++ > target/i386/kvm/kvm.c | 6 ++++++ > target/mips/kvm.c | 5 +++++ > target/ppc/kvm.c | 5 +++++ > target/s390x/kvm.c | 5 +++++ > 11 files changed, 58 insertions(+), 2 deletions(-) > > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c > index 9db74b465e..9ac44ad018 100644 > --- a/accel/kvm/kvm-all.c > +++ b/accel/kvm/kvm-all.c > @@ -2411,6 +2411,11 @@ void kvm_flush_coalesced_mmio_buffer(void) > s->coalesced_flush_in_progress = false; > } > > +bool kvm_cpu_check_are_resettable(void) > +{ > + return kvm_arch_cpu_check_are_resettable(); > +} > + > static void do_kvm_cpu_synchronize_state(CPUState *cpu, run_on_cpu_data arg) > { > if (!cpu->vcpu_dirty) { > diff --git a/include/sysemu/cpus.h b/include/sysemu/cpus.h > index e8156728c6..1cb4f9dbeb 100644 > --- a/include/sysemu/cpus.h > +++ b/include/sysemu/cpus.h > @@ -57,6 +57,8 @@ extern int icount_align_option; > /* Unblock cpu */ > void qemu_cpu_kick_self(void); > > +bool cpus_are_resettable(void); > + > void cpu_synchronize_all_states(void); > void cpu_synchronize_all_post_reset(void); > void cpu_synchronize_all_post_init(void); > diff --git a/include/sysemu/hw_accel.h b/include/sysemu/hw_accel.h > index ffed6192a3..61672f9b32 100644 > --- a/include/sysemu/hw_accel.h > +++ b/include/sysemu/hw_accel.h > @@ -22,4 +22,9 @@ void cpu_synchronize_post_reset(CPUState *cpu); > void cpu_synchronize_post_init(CPUState *cpu); > void cpu_synchronize_pre_loadvm(CPUState *cpu); > > +static inline bool cpu_check_are_resettable(void) > +{ > + return kvm_enabled() ? kvm_cpu_check_are_resettable() : true; > +} > + > #endif /* QEMU_HW_ACCEL_H */ > diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h > index 875ca101e3..3e265cea3d 100644 > --- a/include/sysemu/kvm.h > +++ b/include/sysemu/kvm.h > @@ -573,4 +573,14 @@ int kvm_get_max_memslots(void); > /* Notify resamplefd for EOI of specific interrupts. */ > void kvm_resample_fd_notify(int gsi); > > +/** > + * kvm_cpu_check_are_resettable - return whether CPUs can be reset > + * > + * Returns: true: CPUs are resettable > + * false: CPUs are not resettable > + */ > +bool kvm_cpu_check_are_resettable(void); > + > +bool kvm_arch_cpu_check_are_resettable(void); > + > #endif > diff --git a/softmmu/cpus.c b/softmmu/cpus.c > index 1dc20b9dc3..89de46eae0 100644 > --- a/softmmu/cpus.c > +++ b/softmmu/cpus.c > @@ -194,6 +194,11 @@ void cpu_synchronize_pre_loadvm(CPUState *cpu) > } > } > > +bool cpus_are_resettable(void) > +{ > + return cpu_check_are_resettable(); > +} > + > int64_t cpus_get_virtual_clock(void) > { > /* > diff --git a/softmmu/runstate.c b/softmmu/runstate.c > index 636aab0add..7b4f212d19 100644 > --- a/softmmu/runstate.c > +++ b/softmmu/runstate.c > @@ -523,8 +523,11 @@ void qemu_system_guest_crashloaded(GuestPanicInformation *info) > > void qemu_system_reset_request(ShutdownCause reason) > { > - if (reboot_action == REBOOT_ACTION_SHUTDOWN && > - reason != SHUTDOWN_CAUSE_SUBSYSTEM_RESET) { > + if (!cpus_are_resettable()) { > + error_report("cpus are not resettable, terminating"); > + shutdown_requested = reason; > + } else if (reboot_action == REBOOT_ACTION_SHUTDOWN && > + reason != SHUTDOWN_CAUSE_SUBSYSTEM_RESET) { > shutdown_requested = reason; > } else { > reset_requested = reason; > diff --git a/target/arm/kvm.c b/target/arm/kvm.c > index ffe186de8d..00e124c812 100644 > --- a/target/arm/kvm.c > +++ b/target/arm/kvm.c > @@ -1045,3 +1045,8 @@ int kvm_arch_msi_data_to_gsi(uint32_t data) > { > return (data - 32) & 0xffff; > } > + > +bool kvm_arch_cpu_check_are_resettable(void) > +{ > + return true; > +} > diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c > index aaae79557d..bb6bfc19de 100644 > --- a/target/i386/kvm/kvm.c > +++ b/target/i386/kvm/kvm.c > @@ -27,6 +27,7 @@ > #include "sysemu/kvm_int.h" > #include "sysemu/runstate.h" > #include "kvm_i386.h" > +#include "sev_i386.h" > #include "hyperv.h" > #include "hyperv-proto.h" > > @@ -4788,3 +4789,8 @@ bool kvm_has_waitpkg(void) > { > return has_msr_umwait; > } > + > +bool kvm_arch_cpu_check_are_resettable(void) > +{ > + return !sev_es_enabled(); > +} > diff --git a/target/mips/kvm.c b/target/mips/kvm.c > index 477692566a..a907c59c5e 100644 > --- a/target/mips/kvm.c > +++ b/target/mips/kvm.c > @@ -1289,3 +1289,8 @@ int mips_kvm_type(MachineState *machine, const char *vm_type) > > return -1; > } > + > +bool kvm_arch_cpu_check_are_resettable(void) > +{ > + return true; > +} > diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c > index daf690a678..f45ed11058 100644 > --- a/target/ppc/kvm.c > +++ b/target/ppc/kvm.c > @@ -2947,3 +2947,8 @@ void kvmppc_svm_off(Error **errp) > error_setg_errno(errp, -rc, "KVM_PPC_SVM_OFF ioctl failed"); > } > } > + > +bool kvm_arch_cpu_check_are_resettable(void) > +{ > + return true; > +} > diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c > index b8385e6b95..5c5ba801f1 100644 > --- a/target/s390x/kvm.c > +++ b/target/s390x/kvm.c > @@ -2601,3 +2601,8 @@ void kvm_s390_stop_interrupt(S390CPU *cpu) > > kvm_s390_vcpu_interrupt(cpu, &irq); > } > + > +bool kvm_arch_cpu_check_are_resettable(void) > +{ > + return true; > +} > -- > 2.30.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK