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authorLinus Torvalds <torvalds@linux-foundation.org>2024-05-14 09:18:52 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-05-14 09:18:52 -0700
commit964bbdfdf01d9b365809726313da967cb1dafb96 (patch)
treedcc36fd16a4d7de85076162fed2003dc7c8f30e5
parenta1907ccdfe4a35265f6572e4b8c2da6d1f0a663e (diff)
parente2f4c8c319abd1afbedb7a31877cb569265db1b4 (diff)
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
-rw-r--r--arch/x86/boot/compressed/sev.c197
-rw-r--r--arch/x86/include/asm/sev.h2
-rw-r--r--arch/x86/kernel/sev.c6
-rw-r--r--drivers/virt/coco/sev-guest/sev-guest.c28
4 files changed, 113 insertions, 120 deletions
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
index ec71846d28c9..0457a9d7e515 100644
--- a/arch/x86/boot/compressed/sev.c
+++ b/arch/x86/boot/compressed/sev.c
@@ -335,26 +335,6 @@ finish:
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)
{
/*
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 93ed60080cfe..ca20cc4e5826 100644
--- a/arch/x86/include/asm/sev.h
+++ b/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;
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 995f94467101..3342ed58e168 100644
--- a/arch/x86/kernel/sev.c
+++ b/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;
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 87f241825bc3..654290a8e1ba 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/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));