- Small cleanups and improvements

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Merge tag 'x86_sev_for_v6.10_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SEV updates from Borislav Petkov:

 - Small cleanups and improvements

* tag 'x86_sev_for_v6.10_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/sev: Make the VMPL0 checking more straight forward
  x86/sev: Rename snp_init() in boot/compressed/sev.c
  x86/sev: Shorten struct name snp_secrets_page_layout to snp_secrets_page

arch/x86/boot/compressed/sev.c

@@ -335,26 +335,6 @@ void do_boot_stage2_vc(struct pt_regs *regs, unsigned long exit_code)
 		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ);
 }
 
-static void enforce_vmpl0(void)
-{
-	u64 attrs;
-	int err;
-
-	/*
-	 * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
-	 * higher) privilege level. Here, clear the VMPL1 permission mask of the
-	 * GHCB page. If the guest is not running at VMPL0, this will fail.
-	 *
-	 * If the guest is running at VMPL0, it will succeed. Even if that operation
-	 * modifies permission bits, it is still ok to do so currently because Linux
-	 * SNP guests are supported only on VMPL0 so VMPL1 or higher permission masks
-	 * changing is a don't-care.
-	 */
-	attrs = 1;
-	if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, attrs))
-		sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
-}
-
 /*
  * SNP_FEATURES_IMPL_REQ is the mask of SNP features that will need
  * guest side implementation for proper functioning of the guest. If any
@@ -413,6 +393,85 @@ void snp_check_features(void)
 	}
 }
 
+/* Search for Confidential Computing blob in the EFI config table. */
+static struct cc_blob_sev_info *find_cc_blob_efi(struct boot_params *bp)
+{
+	unsigned long cfg_table_pa;
+	unsigned int cfg_table_len;
+	int ret;
+
+	ret = efi_get_conf_table(bp, &cfg_table_pa, &cfg_table_len);
+	if (ret)
+		return NULL;
+
+	return (struct cc_blob_sev_info *)efi_find_vendor_table(bp, cfg_table_pa,
+								cfg_table_len,
+								EFI_CC_BLOB_GUID);
+}
+
+/*
+ * Initial set up of SNP relies on information provided by the
+ * Confidential Computing blob, which can be passed to the boot kernel
+ * by firmware/bootloader in the following ways:
+ *
+ * - via an entry in the EFI config table
+ * - via a setup_data structure, as defined by the Linux Boot Protocol
+ *
+ * Scan for the blob in that order.
+ */
+static struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	cc_info = find_cc_blob_efi(bp);
+	if (cc_info)
+		goto found_cc_info;
+
+	cc_info = find_cc_blob_setup_data(bp);
+	if (!cc_info)
+		return NULL;
+
+found_cc_info:
+	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
+		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
+
+	return cc_info;
+}
+
+/*
+ * Indicate SNP based on presence of SNP-specific CC blob. Subsequent checks
+ * will verify the SNP CPUID/MSR bits.
+ */
+static bool early_snp_init(struct boot_params *bp)
+{
+	struct cc_blob_sev_info *cc_info;
+
+	if (!bp)
+		return false;
+
+	cc_info = find_cc_blob(bp);
+	if (!cc_info)
+		return false;
+
+	/*
+	 * If a SNP-specific Confidential Computing blob is present, then
+	 * firmware/bootloader have indicated SNP support. Verifying this
+	 * involves CPUID checks which will be more reliable if the SNP
+	 * CPUID table is used. See comments over snp_setup_cpuid_table() for
+	 * more details.
+	 */
+	setup_cpuid_table(cc_info);
+
+	/*
+	 * Pass run-time kernel a pointer to CC info via boot_params so EFI
+	 * config table doesn't need to be searched again during early startup
+	 * phase.
+	 */
+	bp->cc_blob_address = (u32)(unsigned long)cc_info;
+
+	return true;
+}
+
 /*
  * sev_check_cpu_support - Check for SEV support in the CPU capabilities
  *
@@ -463,7 +522,7 @@ void sev_enable(struct boot_params *bp)
 		bp->cc_blob_address = 0;
 
 	/*
-	 * Do an initial SEV capability check before snp_init() which
+	 * Do an initial SEV capability check before early_snp_init() which
 	 * loads the CPUID page and the same checks afterwards are done
 	 * without the hypervisor and are trustworthy.
 	 *
@@ -478,7 +537,7 @@ void sev_enable(struct boot_params *bp)
 	 * Setup/preliminary detection of SNP. This will be sanity-checked
 	 * against CPUID/MSR values later.
 	 */
-	snp = snp_init(bp);
+	snp = early_snp_init(bp);
 
 	/* Now repeat the checks with the SNP CPUID table. */
 
@@ -509,7 +568,20 @@ void sev_enable(struct boot_params *bp)
 		if (!(get_hv_features() & GHCB_HV_FT_SNP))
 			sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
 
-		enforce_vmpl0();
+		/*
+		 * Enforce running at VMPL0.
+		 *
+		 * RMPADJUST modifies RMP permissions of a lesser-privileged (numerically
+		 * higher) privilege level. Here, clear the VMPL1 permission mask of the
+		 * GHCB page. If the guest is not running at VMPL0, this will fail.
+		 *
+		 * If the guest is running at VMPL0, it will succeed. Even if that operation
+		 * modifies permission bits, it is still ok to do so currently because Linux
+		 * SNP guests running at VMPL0 only run at VMPL0, so VMPL1 or higher
+		 * permission mask changes are a don't-care.
+		 */
+		if (rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, 1))
+			sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0);
 	}
 
 	if (snp && !(sev_status & MSR_AMD64_SEV_SNP_ENABLED))
@@ -535,85 +607,6 @@ u64 sev_get_status(void)
 	return m.q;
 }
 
-/* Search for Confidential Computing blob in the EFI config table. */
-static struct cc_blob_sev_info *find_cc_blob_efi(struct boot_params *bp)
-{
-	unsigned long cfg_table_pa;
-	unsigned int cfg_table_len;
-	int ret;
-
-	ret = efi_get_conf_table(bp, &cfg_table_pa, &cfg_table_len);
-	if (ret)
-		return NULL;
-
-	return (struct cc_blob_sev_info *)efi_find_vendor_table(bp, cfg_table_pa,
-								cfg_table_len,
-								EFI_CC_BLOB_GUID);
-}
-
-/*
- * Initial set up of SNP relies on information provided by the
- * Confidential Computing blob, which can be passed to the boot kernel
- * by firmware/bootloader in the following ways:
- *
- * - via an entry in the EFI config table
- * - via a setup_data structure, as defined by the Linux Boot Protocol
- *
- * Scan for the blob in that order.
- */
-static struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp)
-{
-	struct cc_blob_sev_info *cc_info;
-
-	cc_info = find_cc_blob_efi(bp);
-	if (cc_info)
-		goto found_cc_info;
-
-	cc_info = find_cc_blob_setup_data(bp);
-	if (!cc_info)
-		return NULL;
-
-found_cc_info:
-	if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
-		sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED);
-
-	return cc_info;
-}
-
-/*
- * Indicate SNP based on presence of SNP-specific CC blob. Subsequent checks
- * will verify the SNP CPUID/MSR bits.
- */
-bool snp_init(struct boot_params *bp)
-{
-	struct cc_blob_sev_info *cc_info;
-
-	if (!bp)
-		return false;
-
-	cc_info = find_cc_blob(bp);
-	if (!cc_info)
-		return false;
-
-	/*
-	 * If a SNP-specific Confidential Computing blob is present, then
-	 * firmware/bootloader have indicated SNP support. Verifying this
-	 * involves CPUID checks which will be more reliable if the SNP
-	 * CPUID table is used. See comments over snp_setup_cpuid_table() for
-	 * more details.
-	 */
-	setup_cpuid_table(cc_info);
-
-	/*
-	 * Pass run-time kernel a pointer to CC info via boot_params so EFI
-	 * config table doesn't need to be searched again during early startup
-	 * phase.
-	 */
-	bp->cc_blob_address = (u32)(unsigned long)cc_info;
-
-	return true;
-}
-
 void sev_prep_identity_maps(unsigned long top_level_pgt)
 {
 	/*

arch/x86/include/asm/sev.h

@@ -140,7 +140,7 @@ struct secrets_os_area {
 #define VMPCK_KEY_LEN		32
 
 /* See the SNP spec version 0.9 for secrets page format */
-struct snp_secrets_page_layout {
+struct snp_secrets_page {
 	u32 version;
 	u32 imien	: 1,
 	    rsvd1	: 31;

arch/x86/kernel/sev.c

@@ -648,7 +648,7 @@ static u64 __init get_secrets_page(void)
 
 static u64 __init get_snp_jump_table_addr(void)
 {
-	struct snp_secrets_page_layout *layout;
+	struct snp_secrets_page *secrets;
 	void __iomem *mem;
 	u64 pa, addr;
 
@@ -662,9 +662,9 @@ static u64 __init get_snp_jump_table_addr(void)
 		return 0;
 	}
 
-	layout = (__force struct snp_secrets_page_layout *)mem;
+	secrets = (__force struct snp_secrets_page *)mem;
 
-	addr = layout->os_area.ap_jump_table_pa;
+	addr = secrets->os_area.ap_jump_table_pa;
 	iounmap(mem);
 
 	return addr;

drivers/virt/coco/sev-guest/sev-guest.c

@@ -59,7 +59,7 @@ struct snp_guest_dev {
 	 */
 	struct snp_guest_msg secret_request, secret_response;
 
-	struct snp_secrets_page_layout *layout;
+	struct snp_secrets_page *secrets;
 	struct snp_req_data input;
 	union {
 		struct snp_report_req report;
@@ -743,26 +743,26 @@ static const struct file_operations snp_guest_fops = {
 	.unlocked_ioctl = snp_guest_ioctl,
 };
 
-static u8 *get_vmpck(int id, struct snp_secrets_page_layout *layout, u32 **seqno)
+static u8 *get_vmpck(int id, struct snp_secrets_page *secrets, u32 **seqno)
 {
 	u8 *key = NULL;
 
 	switch (id) {
 	case 0:
-		*seqno = &layout->os_area.msg_seqno_0;
-		key = layout->vmpck0;
+		*seqno = &secrets->os_area.msg_seqno_0;
+		key = secrets->vmpck0;
 		break;
 	case 1:
-		*seqno = &layout->os_area.msg_seqno_1;
-		key = layout->vmpck1;
+		*seqno = &secrets->os_area.msg_seqno_1;
+		key = secrets->vmpck1;
 		break;
 	case 2:
-		*seqno = &layout->os_area.msg_seqno_2;
-		key = layout->vmpck2;
+		*seqno = &secrets->os_area.msg_seqno_2;
+		key = secrets->vmpck2;
 		break;
 	case 3:
-		*seqno = &layout->os_area.msg_seqno_3;
-		key = layout->vmpck3;
+		*seqno = &secrets->os_area.msg_seqno_3;
+		key = secrets->vmpck3;
 		break;
 	default:
 		break;
@@ -897,8 +897,8 @@ static void unregister_sev_tsm(void *data)
 
 static int __init sev_guest_probe(struct platform_device *pdev)
 {
-	struct snp_secrets_page_layout *layout;
 	struct sev_guest_platform_data *data;
+	struct snp_secrets_page *secrets;
 	struct device *dev = &pdev->dev;
 	struct snp_guest_dev *snp_dev;
 	struct miscdevice *misc;
@@ -916,7 +916,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 	if (!mapping)
 		return -ENODEV;
 
-	layout = (__force void *)mapping;
+	secrets = (__force void *)mapping;
 
 	ret = -ENOMEM;
 	snp_dev = devm_kzalloc(&pdev->dev, sizeof(struct snp_guest_dev), GFP_KERNEL);
@@ -924,7 +924,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 		goto e_unmap;
 
 	ret = -EINVAL;
-	snp_dev->vmpck = get_vmpck(vmpck_id, layout, &snp_dev->os_area_msg_seqno);
+	snp_dev->vmpck = get_vmpck(vmpck_id, secrets, &snp_dev->os_area_msg_seqno);
 	if (!snp_dev->vmpck) {
 		dev_err(dev, "invalid vmpck id %d\n", vmpck_id);
 		goto e_unmap;
@@ -938,7 +938,7 @@ static int __init sev_guest_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, snp_dev);
 	snp_dev->dev = dev;
-	snp_dev->layout = layout;
+	snp_dev->secrets = secrets;
 
 	/* Allocate the shared page used for the request and response message. */
 	snp_dev->request = alloc_shared_pages(dev, sizeof(struct snp_guest_msg));