From: Joerg Roedel <joro@8bytes.org> To: x86@kernel.org Cc: Joerg Roedel <joro@8bytes.org>, Joerg Roedel <jroedel@suse.de>, hpa@zytor.com, Andy Lutomirski <luto@kernel.org>, Dave Hansen <dave.hansen@linux.intel.com>, Peter Zijlstra <peterz@infradead.org>, Jiri Slaby <jslaby@suse.cz>, Dan Williams <dan.j.williams@intel.com>, Tom Lendacky <thomas.lendacky@amd.com>, Juergen Gross <jgross@suse.com>, Kees Cook <keescook@chromium.org>, David Rientjes <rientjes@google.com>, Cfir Cohen <cfir@google.com>, Erdem Aktas <erdemaktas@google.com>, Masami Hiramatsu <mhiramat@kernel.org>, Mike Stunes <mstunes@vmware.com>, Sean Christopherson <seanjc@google.com>, Martin Radev <martin.b.radev@gmail.com>, Arvind Sankar <nivedita@alum.mit.edu>, linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [RFC PATCH 05/12] x86/sev: Use GHCB protocol version 2 if supported Date: Mon, 5 Jul 2021 10:24:36 +0200 [thread overview] Message-ID: <20210705082443.14721-6-joro@8bytes.org> (raw) In-Reply-To: <20210705082443.14721-1-joro@8bytes.org> From: Joerg Roedel <jroedel@suse.de> Check whether the hypervisor supports GHCB version 2 and use it if available. Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/boot/compressed/sev.c | 10 ++++++++-- arch/x86/include/asm/sev.h | 4 ++-- arch/x86/kernel/sev-shared.c | 17 ++++++++++++++--- 3 files changed, 24 insertions(+), 7 deletions(-) diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index 101e08c67296..7f8416f76be7 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -119,16 +119,22 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, /* Include code for early handlers */ #include "../../kernel/sev-shared.c" +static unsigned int ghcb_protocol; + static u64 sev_get_ghcb_proto_ver(void) { - return GHCB_PROTOCOL_MAX; + return ghcb_protocol; } static bool early_setup_sev_es(void) { - if (!sev_es_negotiate_protocol(NULL)) + struct sev_ghcb_protocol_info info; + + if (!sev_es_negotiate_protocol(&info)) sev_es_terminate(GHCB_SEV_ES_REASON_PROTOCOL_UNSUPPORTED); + ghcb_protocol = info.vm_proto; + if (set_page_decrypted((unsigned long)&boot_ghcb_page)) return false; diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index fa5cd05d3b5b..134a7c9d91b6 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -12,8 +12,8 @@ #include <asm/insn.h> #include <asm/sev-common.h> -#define GHCB_PROTO_OUR 0x0001UL -#define GHCB_PROTOCOL_MAX 1ULL +#define GHCB_PROTOCOL_MIN 1ULL +#define GHCB_PROTOCOL_MAX 2ULL #define GHCB_DEFAULT_USAGE 0ULL #define VMGEXIT() { asm volatile("rep; vmmcall\n\r"); } diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index 36eaac2773ed..40a1ca81bdb8 100644 --- a/arch/x86/kernel/sev-shared.c +++ b/arch/x86/kernel/sev-shared.c @@ -61,6 +61,7 @@ static void __noreturn sev_es_terminate(unsigned int reason) static bool sev_es_negotiate_protocol(struct sev_ghcb_protocol_info *info) { + unsigned int protocol; u64 val; /* Do the GHCB protocol version negotiation */ @@ -71,14 +72,24 @@ static bool sev_es_negotiate_protocol(struct sev_ghcb_protocol_info *info) if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP) return false; - if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTO_OUR || - GHCB_MSR_PROTO_MIN(val) > GHCB_PROTO_OUR) + /* Sanity check untrusted input */ + if (GHCB_MSR_PROTO_MIN(val) > GHCB_MSR_PROTO_MAX(val)) + return false; + + /* Use maximum supported protocol version */ + protocol = min_t(unsigned int, GHCB_MSR_PROTO_MAX(val), GHCB_PROTOCOL_MAX); + + /* + * Hypervisor does not support any protocol version required for this + * kernel. + */ + if (protocol < GHCB_MSR_PROTO_MIN(val)) return false; if (info) { info->hv_proto_min = GHCB_MSR_PROTO_MIN(val); info->hv_proto_max = GHCB_MSR_PROTO_MAX(val); - info->vm_proto = GHCB_PROTO_OUR; + info->vm_proto = protocol; } return true; -- 2.31.1
WARNING: multiple messages have this Message-ID (diff)
From: Joerg Roedel <joro@8bytes.org> To: x86@kernel.org Cc: kvm@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>, Dave Hansen <dave.hansen@linux.intel.com>, virtualization@lists.linux-foundation.org, Arvind Sankar <nivedita@alum.mit.edu>, hpa@zytor.com, Jiri Slaby <jslaby@suse.cz>, Joerg Roedel <joro@8bytes.org>, David Rientjes <rientjes@google.com>, Martin Radev <martin.b.radev@gmail.com>, Tom Lendacky <thomas.lendacky@amd.com>, Joerg Roedel <jroedel@suse.de>, Kees Cook <keescook@chromium.org>, Cfir Cohen <cfir@google.com>, linux-coco@lists.linux.dev, Andy Lutomirski <luto@kernel.org>, Dan Williams <dan.j.williams@intel.com>, Juergen Gross <jgross@suse.com>, Mike Stunes <mstunes@vmware.com>, Sean Christopherson <seanjc@google.com>, linux-kernel@vger.kernel.org, Masami Hiramatsu <mhiramat@kernel.org>, Erdem Aktas <erdemaktas@google.com> Subject: [RFC PATCH 05/12] x86/sev: Use GHCB protocol version 2 if supported Date: Mon, 5 Jul 2021 10:24:36 +0200 [thread overview] Message-ID: <20210705082443.14721-6-joro@8bytes.org> (raw) In-Reply-To: <20210705082443.14721-1-joro@8bytes.org> From: Joerg Roedel <jroedel@suse.de> Check whether the hypervisor supports GHCB version 2 and use it if available. Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/boot/compressed/sev.c | 10 ++++++++-- arch/x86/include/asm/sev.h | 4 ++-- arch/x86/kernel/sev-shared.c | 17 ++++++++++++++--- 3 files changed, 24 insertions(+), 7 deletions(-) diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index 101e08c67296..7f8416f76be7 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -119,16 +119,22 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, /* Include code for early handlers */ #include "../../kernel/sev-shared.c" +static unsigned int ghcb_protocol; + static u64 sev_get_ghcb_proto_ver(void) { - return GHCB_PROTOCOL_MAX; + return ghcb_protocol; } static bool early_setup_sev_es(void) { - if (!sev_es_negotiate_protocol(NULL)) + struct sev_ghcb_protocol_info info; + + if (!sev_es_negotiate_protocol(&info)) sev_es_terminate(GHCB_SEV_ES_REASON_PROTOCOL_UNSUPPORTED); + ghcb_protocol = info.vm_proto; + if (set_page_decrypted((unsigned long)&boot_ghcb_page)) return false; diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index fa5cd05d3b5b..134a7c9d91b6 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -12,8 +12,8 @@ #include <asm/insn.h> #include <asm/sev-common.h> -#define GHCB_PROTO_OUR 0x0001UL -#define GHCB_PROTOCOL_MAX 1ULL +#define GHCB_PROTOCOL_MIN 1ULL +#define GHCB_PROTOCOL_MAX 2ULL #define GHCB_DEFAULT_USAGE 0ULL #define VMGEXIT() { asm volatile("rep; vmmcall\n\r"); } diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index 36eaac2773ed..40a1ca81bdb8 100644 --- a/arch/x86/kernel/sev-shared.c +++ b/arch/x86/kernel/sev-shared.c @@ -61,6 +61,7 @@ static void __noreturn sev_es_terminate(unsigned int reason) static bool sev_es_negotiate_protocol(struct sev_ghcb_protocol_info *info) { + unsigned int protocol; u64 val; /* Do the GHCB protocol version negotiation */ @@ -71,14 +72,24 @@ static bool sev_es_negotiate_protocol(struct sev_ghcb_protocol_info *info) if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP) return false; - if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTO_OUR || - GHCB_MSR_PROTO_MIN(val) > GHCB_PROTO_OUR) + /* Sanity check untrusted input */ + if (GHCB_MSR_PROTO_MIN(val) > GHCB_MSR_PROTO_MAX(val)) + return false; + + /* Use maximum supported protocol version */ + protocol = min_t(unsigned int, GHCB_MSR_PROTO_MAX(val), GHCB_PROTOCOL_MAX); + + /* + * Hypervisor does not support any protocol version required for this + * kernel. + */ + if (protocol < GHCB_MSR_PROTO_MIN(val)) return false; if (info) { info->hv_proto_min = GHCB_MSR_PROTO_MIN(val); info->hv_proto_max = GHCB_MSR_PROTO_MAX(val); - info->vm_proto = GHCB_PROTO_OUR; + info->vm_proto = protocol; } return true; -- 2.31.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-07-05 8:26 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-05 8:24 [RFC PATCH 00/12] x86/sev: KEXEC/KDUMP support for SEV-ES guests Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 01/12] kexec: Allow architecture code to opt-out at runtime Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 02/12] x86/kexec/64: Forbid kexec when running as an SEV-ES guest Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 03/12] x86/sev: Save and print negotiated GHCB protocol version Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 04/12] x86/sev: Do not hardcode " Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel [this message] 2021-07-05 8:24 ` [RFC PATCH 05/12] x86/sev: Use GHCB protocol version 2 if supported Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 06/12] x86/sev: Cache AP Jump Table Address Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 07/12] x86/sev: Setup code to park APs in the AP Jump Table Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 08/12] x86/sev: Park APs on AP Jump Table with GHCB protocol version 2 Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 09/12] x86/sev: Use AP Jump Table blob to stop CPU Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 10/12] x86/sev: Add MMIO handling support to boot/compressed/ code Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 11/12] x86/sev: Handle CLFLUSH MMIO events Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel 2021-07-05 8:24 ` [RFC PATCH 12/12] x86/sev: Support kexec under SEV-ES with AP Jump Table blob Joerg Roedel 2021-07-05 8:24 ` Joerg Roedel
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