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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 34/38] x86/sev: Add snp_msg_seqno() helper
Date: Fri, 20 Aug 2021 10:19:29 -0500	[thread overview]
Message-ID: <20210820151933.22401-35-brijesh.singh@amd.com> (raw)
In-Reply-To: <20210820151933.22401-1-brijesh.singh@amd.com>

The SNP guest request message header contains a message count. The
message count is used while building the IV. The PSP firmware increments
the message count by 1, and expects that next message will be using the
incremented count. The snp_msg_seqno() helper will be used by driver to
get the message sequence counter used in the request message header,
and it will be automatically incremented after the request is successful.
The incremented value is saved in the secrets page so that the kexec'ed
kernel knows from where to begin.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 arch/x86/kernel/sev.c     | 79 +++++++++++++++++++++++++++++++++++++++
 include/linux/sev-guest.h | 37 ++++++++++++++++++
 2 files changed, 116 insertions(+)

diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 319a40fc57ce..f42cd5a8e7bb 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -51,6 +51,8 @@ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE);
  */
 static struct ghcb __initdata *boot_ghcb;
 
+static u64 snp_secrets_phys;
+
 /* #VC handler runtime per-CPU data */
 struct sev_es_runtime_data {
 	struct ghcb ghcb_page;
@@ -2030,6 +2032,80 @@ bool __init handle_vc_boot_ghcb(struct pt_regs *regs)
 		halt();
 }
 
+static struct snp_secrets_page_layout *snp_map_secrets_page(void)
+{
+	u16 __iomem *secrets;
+
+	if (!snp_secrets_phys || !sev_feature_enabled(SEV_SNP))
+		return NULL;
+
+	secrets = ioremap_encrypted(snp_secrets_phys, PAGE_SIZE);
+	if (!secrets)
+		return NULL;
+
+	return (struct snp_secrets_page_layout *)secrets;
+}
+
+static inline u64 snp_read_msg_seqno(void)
+{
+	struct snp_secrets_page_layout *layout;
+	u64 count;
+
+	layout = snp_map_secrets_page();
+	if (!layout)
+		return 0;
+
+	/* Read the current message sequence counter from secrets pages */
+	count = readl(&layout->os_area.msg_seqno_0);
+
+	iounmap(layout);
+
+	/* The sequence counter must begin with 1 */
+	if (!count)
+		return 1;
+
+	return count + 1;
+}
+
+u64 snp_msg_seqno(void)
+{
+	u64 count = snp_read_msg_seqno();
+
+	if (unlikely(!count))
+		return 0;
+
+	/*
+	 * The message sequence counter for the SNP guest request is a
+	 * 64-bit value but the version 2 of GHCB specification defines a
+	 * 32-bit storage for the it.
+	 */
+	if (count >= UINT_MAX)
+		return 0;
+
+	return count;
+}
+EXPORT_SYMBOL_GPL(snp_msg_seqno);
+
+static void snp_gen_msg_seqno(void)
+{
+	struct snp_secrets_page_layout *layout;
+	u64 count;
+
+	layout = snp_map_secrets_page();
+	if (!layout)
+		return;
+
+	/*
+	 * The counter is also incremented by the PSP, so increment it by 2
+	 * and save in secrets page.
+	 */
+	count = readl(&layout->os_area.msg_seqno_0);
+	count += 2;
+
+	writel(count, &layout->os_area.msg_seqno_0);
+	iounmap(layout);
+}
+
 int snp_issue_guest_request(int type, struct snp_guest_request_data *input, unsigned long *fw_err)
 {
 	struct ghcb_state state;
@@ -2077,6 +2153,9 @@ int snp_issue_guest_request(int type, struct snp_guest_request_data *input, unsi
 		ret = -EIO;
 	}
 
+	/* The command was successful, increment the sequence counter */
+	snp_gen_msg_seqno();
+
 e_put:
 	__sev_put_ghcb(&state);
 e_restore_irq:
diff --git a/include/linux/sev-guest.h b/include/linux/sev-guest.h
index 24dd17507789..16b6af24fda7 100644
--- a/include/linux/sev-guest.h
+++ b/include/linux/sev-guest.h
@@ -20,6 +20,41 @@ enum vmgexit_type {
 	GUEST_REQUEST_MAX
 };
 
+/*
+ * The secrets page contains 96-bytes of reserved field that can be used by
+ * the guest OS. The guest OS uses the area to save the message sequence
+ * number for each VMPCK.
+ *
+ * See the GHCB spec section Secret page layout for the format for this area.
+ */
+struct secrets_os_area {
+	u32 msg_seqno_0;
+	u32 msg_seqno_1;
+	u32 msg_seqno_2;
+	u32 msg_seqno_3;
+	u64 ap_jump_table_pa;
+	u8 rsvd[40];
+	u8 guest_usage[32];
+} __packed;
+
+#define VMPCK_KEY_LEN		32
+
+/* See the SNP spec for secrets page format */
+struct snp_secrets_page_layout {
+	u32 version;
+	u32 imien	: 1,
+	    rsvd1	: 31;
+	u32 fms;
+	u32 rsvd2;
+	u8 gosvw[16];
+	u8 vmpck0[VMPCK_KEY_LEN];
+	u8 vmpck1[VMPCK_KEY_LEN];
+	u8 vmpck2[VMPCK_KEY_LEN];
+	u8 vmpck3[VMPCK_KEY_LEN];
+	struct secrets_os_area os_area;
+	u8 rsvd3[3840];
+} __packed;
+
 /*
  * The error code when the data_npages is too small. The error code
  * is defined in the GHCB specification.
@@ -36,6 +71,7 @@ struct snp_guest_request_data {
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 int snp_issue_guest_request(int vmgexit_type, struct snp_guest_request_data *input,
 			    unsigned long *fw_err);
+u64 snp_msg_seqno(void);
 #else
 
 static inline int snp_issue_guest_request(int type, struct snp_guest_request_data *input,
@@ -43,6 +79,7 @@ static inline int snp_issue_guest_request(int type, struct snp_guest_request_dat
 {
 	return -ENODEV;
 }
+static inline u64 snp_msg_seqno(void) { return 0; }
 
 #endif /* CONFIG_AMD_MEM_ENCRYPT */
 #endif /* __LINUX_SEV_GUEST_H__ */
-- 
2.17.1


  parent reply	other threads:[~2021-08-20 15:23 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 ` [PATCH Part1 v5 16/38] x86/kernel: Validate rom memory before accessing when SEV-SNP is active Brijesh Singh
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 ` Brijesh Singh [this message]
2021-08-27 18:41   ` [PATCH Part1 v5 34/38] x86/sev: Add snp_msg_seqno() helper 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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