| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20220307213356.2797205-40-brijesh.singh@amd.com>
Date: Mon, 7 Mar 2022 15:33:49 -0600
From: Brijesh Singh <brijesh.singh@....com>
To: <x86@...nel.org>, <linux-kernel@...r.kernel.org>,
<kvm@...r.kernel.org>, <linux-efi@...r.kernel.org>,
<platform-driver-x86@...r.kernel.org>,
<linux-coco@...ts.linux.dev>, <linux-mm@...ck.org>
CC: Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Joerg Roedel <jroedel@...e.de>,
Tom Lendacky <thomas.lendacky@....com>,
"H. Peter Anvin" <hpa@...or.com>, Ard Biesheuvel <ardb@...nel.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
"Vitaly Kuznetsov" <vkuznets@...hat.com>,
Jim Mattson <jmattson@...gle.com>,
"Andy Lutomirski" <luto@...nel.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Sergio Lopez <slp@...hat.com>, Peter Gonda <pgonda@...gle.com>,
"Peter Zijlstra" <peterz@...radead.org>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
David Rientjes <rientjes@...gle.com>,
Dov Murik <dovmurik@...ux.ibm.com>,
Tobin Feldman-Fitzthum <tobin@....com>,
Borislav Petkov <bp@...en8.de>,
Michael Roth <michael.roth@....com>,
Vlastimil Babka <vbabka@...e.cz>,
"Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
Andi Kleen <ak@...ux.intel.com>,
"Dr . David Alan Gilbert" <dgilbert@...hat.com>,
<brijesh.ksingh@...il.com>, <tony.luck@...el.com>,
<marcorr@...gle.com>, <sathyanarayanan.kuppuswamy@...ux.intel.com>,
Brijesh Singh <brijesh.singh@....com>
Subject: [PATCH v12 39/46] x86/sev: Use firmware-validated CPUID for SEV-SNP guests
From: Michael Roth <michael.roth@....com>
SEV-SNP guests will be provided the location of special 'secrets' and
'CPUID' pages via the Confidential Computing blob. This blob is
provided to the run-time kernel either through a bootparams field that
was initialized by the boot/compressed kernel, or via a setup_data
structure as defined by the Linux Boot Protocol.
Locate the Confidential Computing blob from these sources and, if found,
use the provided CPUID page/table address to create a copy that the
run-time kernel will use when servicing CPUID instructions via a #VC
handler.
Signed-off-by: Michael Roth <michael.roth@....com>
Signed-off-by: Brijesh Singh <brijesh.singh@....com>
---
arch/x86/boot/compressed/sev.c | 37 ----------------------------------
arch/x86/kernel/sev-shared.c | 37 ++++++++++++++++++++++++++++++++++
arch/x86/kernel/sev.c | 24 ++++++++++++++++++++++
3 files changed, 61 insertions(+), 37 deletions(-)
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index 2911137bf37f..79a59027f3d8 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -381,43 +381,6 @@ static struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp)
return cc_info;
}
-/*
- * Initialize the kernel's copy of the SNP CPUID table, and set up the
- * pointer that will be used to access it.
- *
- * Maintaining a direct mapping of the SNP CPUID table used by firmware would
- * be possible as an alternative, but the approach is brittle since the
- * mapping needs to be updated in sync with all the changes to virtual memory
- * layout and related mapping facilities throughout the boot process.
- */
-static void setup_cpuid_table(const struct cc_blob_sev_info *cc_info)
-{
- const struct snp_cpuid_table *cpuid_table_fw, *cpuid_table;
- int i;
-
- if (!cc_info || !cc_info->cpuid_phys || cc_info->cpuid_len < PAGE_SIZE)
- sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_CPUID);
-
- cpuid_table_fw = (const struct snp_cpuid_table *)cc_info->cpuid_phys;
- if (!cpuid_table_fw->count || cpuid_table_fw->count > SNP_CPUID_COUNT_MAX)
- sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_CPUID);
-
- cpuid_table = snp_cpuid_get_table();
- memcpy((void *)cpuid_table, cpuid_table_fw, sizeof(*cpuid_table));
-
- /* Initialize CPUID ranges for range-checking. */
- for (i = 0; i < cpuid_table->count; i++) {
- const struct snp_cpuid_fn *fn = &cpuid_table->fn[i];
-
- if (fn->eax_in == 0x0)
- cpuid_std_range_max = fn->eax;
- else if (fn->eax_in == 0x40000000)
- cpuid_hyp_range_max = fn->eax;
- else if (fn->eax_in == 0x80000000)
- cpuid_ext_range_max = fn->eax;
- }
-}
-
/*
* Indicate SNP based on presence of SNP-specific CC blob. Subsequent checks
* will verify the SNP CPUID/MSR bits.
diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c
index a7a1c0fb298e..2b4270d5559e 100644
--- a/arch/x86/kernel/sev-shared.c
+++ b/arch/x86/kernel/sev-shared.c
@@ -964,3 +964,40 @@ static struct cc_blob_sev_info *find_cc_blob_setup_data(struct boot_params *bp)
return NULL;
}
+
+/*
+ * Initialize the kernel's copy of the SNP CPUID table, and set up the
+ * pointer that will be used to access it.
+ *
+ * Maintaining a direct mapping of the SNP CPUID table used by firmware would
+ * be possible as an alternative, but the approach is brittle since the
+ * mapping needs to be updated in sync with all the changes to virtual memory
+ * layout and related mapping facilities throughout the boot process.
+ */
+static void __init setup_cpuid_table(const struct cc_blob_sev_info *cc_info)
+{
+ const struct snp_cpuid_table *cpuid_table_fw, *cpuid_table;
+ int i;
+
+ if (!cc_info || !cc_info->cpuid_phys || cc_info->cpuid_len < PAGE_SIZE)
+ sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_CPUID);
+
+ cpuid_table_fw = (const struct snp_cpuid_table *)cc_info->cpuid_phys;
+ if (!cpuid_table_fw->count || cpuid_table_fw->count > SNP_CPUID_COUNT_MAX)
+ sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_CPUID);
+
+ cpuid_table = snp_cpuid_get_table();
+ memcpy((void *)cpuid_table, cpuid_table_fw, sizeof(*cpuid_table));
+
+ /* Initialize CPUID ranges for range-checking. */
+ for (i = 0; i < cpuid_table->count; i++) {
+ const struct snp_cpuid_fn *fn = &cpuid_table->fn[i];
+
+ if (fn->eax_in == 0x0)
+ cpuid_std_range_max = fn->eax;
+ else if (fn->eax_in == 0x40000000)
+ cpuid_hyp_range_max = fn->eax;
+ else if (fn->eax_in == 0x80000000)
+ cpuid_ext_range_max = fn->eax;
+ }
+}
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 5a7df617394b..c6b2e0c58255 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -34,6 +34,7 @@
#include <asm/cpu.h>
#include <asm/apic.h>
#include <asm/cpuid.h>
+#include <asm/cmdline.h>
#define DR7_RESET_VALUE 0x400
@@ -2028,6 +2029,8 @@ bool __init snp_init(struct boot_params *bp)
if (!cc_info)
return false;
+ setup_cpuid_table(cc_info);
+
/*
* The CC blob will be used later to access the secrets page. Cache
* it here like the boot kernel does.
@@ -2041,3 +2044,24 @@ void __init snp_abort(void)
{
sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
}
+
+/*
+ * It is useful from an auditing/testing perspective to provide an easy way
+ * for the guest owner to know that the CPUID table has been initialized as
+ * expected, but that initialization happens too early in boot to print any
+ * sort of indicator, and there's not really any other good place to do it,
+ * so do it here.
+ */
+static int __init report_cpuid_table(void)
+{
+ const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table();
+
+ if (!cpuid_table->count)
+ return 0;
+
+ pr_info("Using SNP CPUID table, %d entries present.\n",
+ cpuid_table->count);
+
+ return 0;
+}
+arch_initcall(report_cpuid_table);
--
2.25.1
Powered by blists - more mailing lists