From: Brijesh Singh <brijesh.singh@amd.com>
To: x86@kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, linux-efi@vger.kernel.org,
platform-driver-x86@vger.kernel.org, linux-coco@lists.linux.dev,
linux-mm@kvack.org, linux-crypto@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
Tom Lendacky <thomas.lendacky@amd.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Ard Biesheuvel <ardb@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
David Rientjes <rientjes@google.com>,
tony.luck@intel.com, npmccallum@redhat.com,
Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH Part1 RFC v3 06/22] x86/sev: check SEV-SNP features support
Date: Wed, 2 Jun 2021 09:04:00 -0500 [thread overview]
Message-ID: <20210602140416.23573-7-brijesh.singh@amd.com> (raw)
In-Reply-To: <20210602140416.23573-1-brijesh.singh@amd.com>
Version 2 of the GHCB specification added the advertisement of features
that are supported by the hypervisor. If hypervisor supports the SEV-SNP
then it must set the SEV-SNP features bit to indicate that the base
SEV-SNP is supported.
Check the SEV-SNP feature while establishing the GHCB, if failed,
terminate the guest.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
arch/x86/boot/compressed/sev.c | 22 ++++++++++++++++++++++
arch/x86/include/asm/sev-common.h | 3 +++
arch/x86/kernel/sev-shared.c | 11 +++++++++++
arch/x86/kernel/sev.c | 4 ++++
4 files changed, 40 insertions(+)
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 87621f4e4703..0745ea61d32e 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -25,6 +25,7 @@
struct ghcb boot_ghcb_page __aligned(PAGE_SIZE);
struct ghcb *boot_ghcb;
+static u64 msr_sev_status;
/*
* Copy a version of this function here - insn-eval.c can't be used in
@@ -119,11 +120,32 @@ static enum es_result vc_read_mem(struct es_em_ctxt *ctxt,
/* Include code for early handlers */
#include "../../kernel/sev-shared.c"
+static inline bool sev_snp_enabled(void)
+{
+ unsigned long low, high;
+
+ if (!msr_sev_status) {
+ asm volatile("rdmsr\n"
+ : "=a" (low), "=d" (high)
+ : "c" (MSR_AMD64_SEV));
+ msr_sev_status = (high << 32) | low;
+ }
+
+ return msr_sev_status & MSR_AMD64_SEV_SNP_ENABLED;
+}
+
static bool early_setup_sev_es(void)
{
if (!sev_es_negotiate_protocol())
sev_es_terminate(0, GHCB_SEV_ES_PROT_UNSUPPORTED);
+ /*
+ * If SEV-SNP is enabled, then check if the hypervisor supports the SEV-SNP
+ * features.
+ */
+ if (sev_snp_enabled() && !sev_snp_check_hypervisor_features())
+ sev_es_terminate(0, GHCB_SEV_ES_SNP_UNSUPPORTED);
+
if (set_page_decrypted((unsigned long)&boot_ghcb_page))
return false;
diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h
index 981fff2257b9..3ebf00772f26 100644
--- a/arch/x86/include/asm/sev-common.h
+++ b/arch/x86/include/asm/sev-common.h
@@ -51,6 +51,8 @@
#define GHCB_MSR_HV_FT_POS 12
#define GHCB_MSR_HV_FT_MASK GENMASK_ULL(51, 0)
+#define GHCB_HV_FT_SNP BIT_ULL(0)
+
#define GHCB_MSR_HV_FT_RESP_VAL(v) \
(((unsigned long)((v) & GHCB_MSR_HV_FT_MASK) >> GHCB_MSR_HV_FT_POS))
@@ -65,6 +67,7 @@
#define GHCB_SEV_ES_GEN_REQ 0
#define GHCB_SEV_ES_PROT_UNSUPPORTED 1
+#define GHCB_SEV_ES_SNP_UNSUPPORTED 2
#define GHCB_RESP_CODE(v) ((v) & GHCB_MSR_INFO_MASK)
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index 94957c5bdb51..b8312ad66120 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -32,6 +32,17 @@ static bool __init sev_es_check_cpu_features(void)
return true;
}
+static bool __init sev_snp_check_hypervisor_features(void)
+{
+ if (ghcb_version < 2)
+ return false;
+
+ if (!(hv_features & GHCB_HV_FT_SNP))
+ return false;
+
+ return true;
+}
+
static void __noreturn sev_es_terminate(unsigned int set, unsigned int reason)
{
u64 val = GHCB_MSR_TERM_REQ;
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 77a754365ba9..9b70b7332614 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -609,6 +609,10 @@ static bool __init sev_es_setup_ghcb(void)
if (!sev_es_negotiate_protocol())
return false;
+ /* If SNP is active, make sure that hypervisor supports the feature. */
+ if (sev_feature_enabled(SEV_SNP) && !sev_snp_check_hypervisor_features())
+ sev_es_terminate(0, GHCB_SEV_ES_SNP_UNSUPPORTED);
+
/*
* Clear the boot_ghcb. The first exception comes in before the bss
* section is cleared.
--
2.17.1
next prev parent reply other threads:[~2021-06-02 14:04 UTC|newest]
Thread overview: 100+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-02 14:03 [PATCH Part1 RFC v3 00/22] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2021-06-02 14:03 ` [PATCH Part1 RFC v3 01/22] x86/sev: shorten GHCB terminate macro names Brijesh Singh
2021-06-08 15:54 ` Venu Busireddy
2021-06-02 14:03 ` [PATCH Part1 RFC v3 02/22] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
2021-06-08 15:59 ` Venu Busireddy
2021-06-08 16:51 ` Brijesh Singh
2021-06-02 14:03 ` [PATCH Part1 RFC v3 03/22] x86/sev: Save the negotiated GHCB version Brijesh Singh
2021-06-03 19:57 ` Borislav Petkov
2021-06-08 17:35 ` Venu Busireddy
2021-06-02 14:03 ` [PATCH Part1 RFC v3 04/22] x86/mm: Add sev_feature_enabled() helper Brijesh Singh
2021-06-05 10:50 ` Borislav Petkov
2021-06-02 14:03 ` [PATCH Part1 RFC v3 05/22] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
2021-06-07 14:19 ` Borislav Petkov
2021-06-07 14:58 ` Brijesh Singh
2021-06-02 14:04 ` Brijesh Singh [this message]
2021-06-07 14:54 ` [PATCH Part1 RFC v3 06/22] x86/sev: check SEV-SNP features support Borislav Petkov
2021-06-07 16:01 ` Brijesh Singh
2021-06-17 18:46 ` Brijesh Singh
2021-06-18 5:46 ` Borislav Petkov
2021-06-02 14:04 ` [PATCH Part1 RFC v3 07/22] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2021-06-07 15:35 ` Borislav Petkov
2021-06-02 14:04 ` [PATCH Part1 RFC v3 08/22] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2021-06-08 11:12 ` Borislav Petkov
2021-06-08 15:58 ` Brijesh Singh
2021-06-16 10:21 ` Borislav Petkov
2021-06-02 14:04 ` [PATCH Part1 RFC v3 09/22] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2021-06-09 17:47 ` Borislav Petkov
2021-06-14 12:28 ` Brijesh Singh
2021-06-02 14:04 ` [PATCH Part1 RFC v3 10/22] x86/sev: " Brijesh Singh
2021-06-10 5:49 ` Borislav Petkov
2021-06-14 12:29 ` Brijesh Singh
2021-06-02 14:04 ` [PATCH Part1 RFC v3 11/22] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2021-06-10 15:50 ` Borislav Petkov
2021-06-14 12:45 ` Brijesh Singh
2021-06-14 19:03 ` Borislav Petkov
2021-06-14 21:01 ` Brijesh Singh
2021-06-16 10:07 ` Borislav Petkov
2021-06-16 11:00 ` Brijesh Singh
2021-06-16 12:03 ` Borislav Petkov
2021-06-16 12:49 ` Brijesh Singh
2021-06-16 13:02 ` Borislav Petkov
2021-06-16 13:10 ` Brijesh Singh
2021-06-16 14:36 ` Brijesh Singh
2021-06-16 14:37 ` Brijesh Singh
2021-06-16 13:06 ` Dr. David Alan Gilbert
2021-06-02 14:04 ` [PATCH Part1 RFC v3 12/22] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
2021-06-10 16:06 ` Borislav Petkov
2021-06-02 14:04 ` [PATCH Part1 RFC v3 13/22] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
2021-06-02 14:04 ` [PATCH Part1 RFC v3 14/22] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
2021-06-11 9:44 ` Borislav Petkov
2021-06-14 13:05 ` Brijesh Singh
2021-06-14 19:27 ` Borislav Petkov
2021-06-02 14:04 ` [PATCH Part1 RFC v3 15/22] KVM: SVM: define new SEV_FEATURES field in the VMCB Save State Area Brijesh Singh
2021-06-02 14:04 ` [PATCH Part1 RFC v3 16/22] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
2021-06-14 10:58 ` Borislav Petkov
2021-06-14 19:34 ` Tom Lendacky
2021-06-14 19:50 ` Borislav Petkov
2021-06-02 14:04 ` [PATCH Part1 RFC v3 17/22] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
2021-06-02 14:04 ` [PATCH Part1 RFC v3 18/22] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
2021-06-02 14:04 ` [PATCH Part1 RFC v3 19/22] x86/sev-snp: SEV-SNP AP creation support Brijesh Singh
2021-06-16 13:07 ` Borislav Petkov
2021-06-16 16:13 ` Tom Lendacky
2021-06-02 14:04 ` [PATCH Part1 RFC v3 20/22] x86/boot: Add Confidential Computing address to setup_header Brijesh Singh
2021-06-18 6:08 ` Borislav Petkov
2021-06-18 13:57 ` Brijesh Singh
2021-06-18 15:05 ` Borislav Petkov
2021-06-23 4:30 ` Michael Roth
2021-06-23 10:22 ` Borislav Petkov
2021-06-24 3:19 ` Michael Roth
2021-06-24 7:27 ` Borislav Petkov
2021-06-24 12:26 ` Michael Roth
2021-06-24 12:34 ` Michael Roth
2021-06-24 12:54 ` Borislav Petkov
2021-06-24 14:11 ` Michael Roth
2021-06-25 14:48 ` Borislav Petkov
2021-06-25 15:24 ` Brijesh Singh
2021-06-25 17:01 ` Borislav Petkov
2021-06-25 18:14 ` Michael Roth
2021-06-28 13:43 ` Borislav Petkov
2021-06-24 13:09 ` Kuppuswamy, Sathyanarayanan
2021-06-02 14:04 ` [PATCH Part1 RFC v3 21/22] x86/sev: Register SNP guest request platform device Brijesh Singh
2021-06-04 11:28 ` Sergio Lopez
2021-06-09 19:24 ` Dr. David Alan Gilbert
2021-06-11 13:16 ` Tom Lendacky
2021-06-14 17:15 ` Dr. David Alan Gilbert
2021-06-14 18:24 ` Brijesh Singh
2021-06-14 13:20 ` Brijesh Singh
2021-06-14 17:23 ` Dr. David Alan Gilbert
2021-06-14 20:50 ` Brijesh Singh
2021-06-18 9:46 ` Borislav Petkov
2021-06-18 13:59 ` Brijesh Singh
2021-06-02 14:04 ` [PATCH Part1 RFC v3 22/22] virt: Add SEV-SNP guest driver Brijesh Singh
2021-06-30 13:35 ` Borislav Petkov
2021-06-30 16:26 ` Brijesh Singh
2021-07-01 18:03 ` Borislav Petkov
2021-07-01 21:32 ` Brijesh Singh
2021-07-03 16:19 ` Borislav Petkov
2021-07-05 10:39 ` Brijesh Singh
2021-06-07 19:15 ` [PATCH Part1 RFC v3 00/22] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Venu Busireddy
2021-06-07 19:17 ` Borislav Petkov
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