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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
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>,
	Dov Murik <dovmurik@linux.ibm.com>,
	Tobin Feldman-Fitzthum <tobin@ibm.com>,
	Borislav Petkov <bp@alien8.de>,
	Michael Roth <michael.roth@amd.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	"Kirill A . Shutemov" <kirill@shutemov.name>,
	Andi Kleen <ak@linux.intel.com>,
	tony.luck@intel.com, marcorr@google.com,
	sathyanarayanan.kuppuswamy@linux.intel.com,
	Brijesh Singh <brijesh.singh@amd.com>
Subject: [PATCH Part1 v5 16/38] x86/kernel: Validate rom memory before accessing when SEV-SNP is active
Date: Fri, 20 Aug 2021 10:19:11 -0500	[thread overview]
Message-ID: <20210820151933.22401-17-brijesh.singh@amd.com> (raw)
In-Reply-To: <20210820151933.22401-1-brijesh.singh@amd.com>

The probe_roms() access the memory range (0xc0000 - 0x10000) to probe
various ROMs. The memory range is not part of the E820 system RAM
range. The memory range is mapped as private (i.e encrypted) in page
table.

When SEV-SNP is active, all the private memory must be validated before
the access. The ROM range was not part of E820 map, so the guest BIOS
did not validate it. An access to invalidated memory will cause a VC
exception. The guest does not support handling not-validated VC exception
yet, so validate the ROM memory regions before it is accessed.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/kernel/probe_roms.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/probe_roms.c b/arch/x86/kernel/probe_roms.c
index 9e1def3744f2..9c09df86d167 100644
--- a/arch/x86/kernel/probe_roms.c
+++ b/arch/x86/kernel/probe_roms.c
@@ -21,6 +21,7 @@
 #include <asm/sections.h>
 #include <asm/io.h>
 #include <asm/setup_arch.h>
+#include <asm/sev.h>
 
 static struct resource system_rom_resource = {
 	.name	= "System ROM",
@@ -197,11 +198,21 @@ static int __init romchecksum(const unsigned char *rom, unsigned long length)
 
 void __init probe_roms(void)
 {
-	const unsigned char *rom;
 	unsigned long start, length, upper;
+	const unsigned char *rom;
 	unsigned char c;
 	int i;
 
+	/*
+	 * The ROM memory is not part of the E820 system RAM and is not pre-validated
+	 * by the BIOS. The kernel page table maps the ROM region as encrypted memory,
+	 * the SEV-SNP requires the encrypted memory must be validated before the
+	 * access. Validate the ROM before accessing it.
+	 */
+	snp_prep_memory(video_rom_resource.start,
+			((system_rom_resource.end + 1) - video_rom_resource.start),
+			SNP_PAGE_STATE_PRIVATE);
+
 	/* video rom */
 	upper = adapter_rom_resources[0].start;
 	for (start = video_rom_resource.start; start < upper; start += 2048) {
-- 
2.17.1


  parent reply	other threads:[~2021-08-20 15:22 UTC|newest]

Thread overview: 123+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-20 15:18 [PATCH Part1 v5 00/38] Add AMD Secure Nested Paging (SEV-SNP) Guest Support Brijesh Singh
2021-08-20 15:18 ` [PATCH Part1 v5 01/38] x86/mm: Add sev_feature_enabled() helper Brijesh Singh
2021-08-20 15:18 ` [PATCH Part1 v5 02/38] x86/sev: Shorten GHCB terminate macro names Brijesh Singh
2021-08-20 15:18 ` [PATCH Part1 v5 03/38] x86/sev: Get rid of excessive use of defines Brijesh Singh
2021-08-20 15:18 ` [PATCH Part1 v5 04/38] x86/head64: Carve out the guest encryption postprocessing into a helper Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 05/38] x86/sev: Define the Linux specific guest termination reasons Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 06/38] x86/sev: Save the negotiated GHCB version Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 07/38] x86/sev: Add support for hypervisor feature VMGEXIT Brijesh Singh
2021-08-23  9:47   ` Borislav Petkov
2021-08-23 18:25     ` Brijesh Singh
2021-08-23 18:34       ` Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 08/38] x86/sev: Check SEV-SNP features support Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 09/38] x86/sev: Add a helper for the PVALIDATE instruction Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 10/38] x86/sev: Check the vmpl level Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 11/38] x86/compressed: Add helper for validating pages in the decompression stage Brijesh Singh
2021-08-23 14:16   ` Borislav Petkov
2021-08-23 18:55     ` Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 12/38] x86/compressed: Register GHCB memory when SEV-SNP is active Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 13/38] x86/sev: " Brijesh Singh
2021-08-23 17:35   ` Borislav Petkov
2021-08-23 18:56     ` Brijesh Singh
2021-08-23 19:45       ` [PATCH] x86/sev: Remove do_early_exception() forward declarations Borislav Petkov
2021-08-23 20:06         ` Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 14/38] x86/sev: Add helper for validating pages in early enc attribute changes Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 15/38] x86/kernel: Make the bss.decrypted section shared in RMP table Brijesh Singh
2021-08-20 15:19 ` Brijesh Singh [this message]
2021-08-20 15:19 ` [PATCH Part1 v5 17/38] x86/mm: Add support to validate memory when changing C-bit Brijesh Singh
2021-08-25 11:06   ` Borislav Petkov
2021-08-25 13:54     ` Brijesh Singh
2021-08-25 14:00       ` Borislav Petkov
2021-08-27 17:09   ` Borislav Petkov
2021-08-20 15:19 ` [PATCH Part1 v5 18/38] KVM: SVM: Define sev_features and vmpl field in the VMSA Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 19/38] KVM: SVM: Create a separate mapping for the SEV-ES save area Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 20/38] KVM: SVM: Create a separate mapping for the GHCB " Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 21/38] KVM: SVM: Update the SEV-ES save area mapping Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 22/38] x86/sev: Use SEV-SNP AP creation to start secondary CPUs Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 23/38] x86/head/64: set up a startup %gs for stack protector Brijesh Singh
2021-08-25 14:29   ` Borislav Petkov
2021-08-25 15:18     ` Michael Roth
2021-08-25 16:29       ` Borislav Petkov
2021-08-27 13:38         ` Michael Roth
2021-08-31  8:03           ` Borislav Petkov
2021-08-31 23:30             ` Michael Roth
2021-08-25 15:07   ` Joerg Roedel
2021-08-25 17:07     ` Michael Roth
2021-08-20 15:19 ` [PATCH Part1 v5 24/38] x86/sev: move MSR-based VMGEXITs for CPUID to helper Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 25/38] KVM: x86: move lookup of indexed CPUID leafs " Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 26/38] x86/compressed/acpi: move EFI config table access to common code Brijesh Singh
2021-08-25 15:18   ` Borislav Petkov
2021-08-25 17:14     ` Michael Roth
2021-08-20 15:19 ` [PATCH Part1 v5 27/38] x86/boot: Add Confidential Computing type to setup_data Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 28/38] x86/compressed/64: enable SEV-SNP-validated CPUID in #VC handler Brijesh Singh
2021-08-25 19:19   ` Borislav Petkov
2021-08-27 16:46     ` Michael Roth
2021-08-31 10:04       ` Borislav Petkov
2021-09-01  1:03         ` Michael Roth
2021-09-02 10:53           ` Borislav Petkov
2021-08-20 15:19 ` [PATCH Part1 v5 29/38] x86/boot: add a pointer to Confidential Computing blob in bootparams Brijesh Singh
2021-08-27 13:51   ` Borislav Petkov
2021-08-27 18:48     ` Michael Roth
2021-08-20 15:19 ` [PATCH Part1 v5 30/38] x86/compressed/64: store Confidential Computing blob address " Brijesh Singh
2021-08-27 14:15   ` Borislav Petkov
2021-08-27 19:09     ` Michael Roth
2021-08-31 10:26       ` Borislav Petkov
2021-08-20 15:19 ` [PATCH Part1 v5 31/38] x86/compressed/64: add identity mapping for Confidential Computing blob Brijesh Singh
2021-08-27 14:43   ` Borislav Petkov
2021-08-20 15:19 ` [PATCH Part1 v5 32/38] x86/sev: enable SEV-SNP-validated CPUID in #VC handlers Brijesh Singh
2021-08-27 15:18   ` Borislav Petkov
2021-08-27 15:47     ` Brijesh Singh
2021-08-27 16:56       ` Borislav Petkov
2021-08-27 18:39       ` Michael Roth
2021-08-27 18:32     ` Michael Roth
2021-08-30 16:03       ` Michael Roth
2021-08-31 16:22       ` Borislav Petkov
2021-09-01  1:16         ` Michael Roth
2021-09-02 11:05           ` Borislav Petkov
2021-08-20 15:19 ` [PATCH Part1 v5 33/38] x86/sev: Provide support for SNP guest request NAEs Brijesh Singh
2021-08-27 17:44   ` Borislav Petkov
2021-08-27 18:07     ` Brijesh Singh
2021-08-27 18:13       ` Borislav Petkov
2021-08-27 18:27         ` Brijesh Singh
2021-08-27 18:38           ` Borislav Petkov
2021-08-27 19:57       ` Tom Lendacky
2021-08-27 20:17         ` Borislav Petkov
2021-08-27 20:31           ` Tom Lendacky
2021-08-20 15:19 ` [PATCH Part1 v5 34/38] x86/sev: Add snp_msg_seqno() helper Brijesh Singh
2021-08-27 18:41   ` Borislav Petkov
2021-08-30 15:07     ` Brijesh Singh
2021-09-02 11:26       ` Borislav Petkov
2021-09-02 15:27         ` Brijesh Singh
2021-08-31 20:46   ` Dov Murik
2021-08-31 21:13     ` Brijesh Singh
2021-09-09 14:54   ` Peter Gonda
2021-09-09 15:26     ` Brijesh Singh
2021-09-09 15:43       ` Peter Gonda
2021-09-09 16:17         ` Brijesh Singh
2021-09-09 16:21           ` Peter Gonda
2021-09-09 19:26             ` Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 35/38] x86/sev: Register SNP guest request platform device Brijesh Singh
2021-08-31 11:37   ` Dov Murik
2021-08-31 16:03     ` Brijesh Singh
2021-09-02 16:40   ` Borislav Petkov
2021-09-02 19:58     ` Brijesh Singh
2021-09-03  8:15       ` Dov Murik
2021-09-03 12:08         ` Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 36/38] virt: Add SEV-SNP guest driver Brijesh Singh
2021-09-06 17:38   ` Borislav Petkov
2021-09-07 13:35     ` Brijesh Singh
2021-09-08 13:44       ` Borislav Petkov
2021-08-20 15:19 ` [PATCH Part1 v5 37/38] virt: sevguest: Add support to derive key Brijesh Singh
2021-08-31 18:59   ` Dov Murik
2021-08-31 21:04     ` Brijesh Singh
2021-09-01  5:33       ` Dov Murik
2021-09-08 14:00   ` Borislav Petkov
2021-09-08 21:44     ` Brijesh Singh
2021-08-20 15:19 ` [PATCH Part1 v5 38/38] virt: sevguest: Add support to get extended report Brijesh Singh
2021-08-31 20:22   ` Dov Murik
2021-08-31 21:11     ` Brijesh Singh
2021-09-01  8:32       ` Dov Murik
2021-09-08 17:53   ` Borislav Petkov
2021-09-15 11:46     ` Brijesh Singh
2021-09-15 10:02   ` Dr. David Alan Gilbert
2021-09-15 11:53     ` Brijesh Singh

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