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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt21
-rw-r--r--arch/x86/kvm/svm/sev.c68
-rw-r--r--drivers/crypto/ccp/sev-dev.c127
-rw-r--r--drivers/crypto/ccp/sev-dev.h6
-rw-r--r--include/linux/psp-sev.h44
-rw-r--r--include/uapi/linux/psp-sev.h10
6 files changed, 249 insertions, 27 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 5a7a83c411e9..b0560d2a2114 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2957,6 +2957,27 @@
(enabled). Disable by KVM if hardware lacks support
for NPT.
+ kvm-amd.ciphertext_hiding_asids=
+ [KVM,AMD] Ciphertext hiding prevents disallowed accesses
+ to SNP private memory from reading ciphertext. Instead,
+ reads will see constant default values (0xff).
+
+ If ciphertext hiding is enabled, the joint SEV-ES and
+ SEV-SNP ASID space is partitioned into separate SEV-ES
+ and SEV-SNP ASID ranges, with the SEV-SNP range being
+ [1..max_snp_asid] and the SEV-ES range being
+ (max_snp_asid..min_sev_asid), where min_sev_asid is
+ enumerated by CPUID.0x.8000_001F[EDX].
+
+ A non-zero value enables SEV-SNP ciphertext hiding and
+ adjusts the ASID ranges for SEV-ES and SEV-SNP guests.
+ KVM caps the number of SEV-SNP ASIDs at the maximum
+ possible value, e.g. specifying -1u will assign all
+ joint SEV-ES and SEV-SNP ASIDs to SEV-SNP. Note,
+ assigning all joint ASIDs to SEV-SNP, i.e. configuring
+ max_snp_asid == min_sev_asid-1, will effectively make
+ SEV-ES unusable.
+
kvm-arm.mode=
[KVM,ARM,EARLY] Select one of KVM/arm64's modes of
operation.
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 81ee31481eaa..aacfbffa3af5 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -58,6 +58,9 @@ static bool sev_es_debug_swap_enabled = true;
module_param_named(debug_swap, sev_es_debug_swap_enabled, bool, 0444);
static u64 sev_supported_vmsa_features;
+static unsigned int nr_ciphertext_hiding_asids;
+module_param_named(ciphertext_hiding_asids, nr_ciphertext_hiding_asids, uint, 0444);
+
#define AP_RESET_HOLD_NONE 0
#define AP_RESET_HOLD_NAE_EVENT 1
#define AP_RESET_HOLD_MSR_PROTO 2
@@ -84,6 +87,10 @@ static DECLARE_RWSEM(sev_deactivate_lock);
static DEFINE_MUTEX(sev_bitmap_lock);
unsigned int max_sev_asid;
static unsigned int min_sev_asid;
+static unsigned int max_sev_es_asid;
+static unsigned int min_sev_es_asid;
+static unsigned int max_snp_asid;
+static unsigned int min_snp_asid;
static unsigned long sev_me_mask;
static unsigned int nr_asids;
static unsigned long *sev_asid_bitmap;
@@ -180,20 +187,34 @@ static void sev_misc_cg_uncharge(struct kvm_sev_info *sev)
misc_cg_uncharge(type, sev->misc_cg, 1);
}
-static int sev_asid_new(struct kvm_sev_info *sev)
+static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
{
/*
* SEV-enabled guests must use asid from min_sev_asid to max_sev_asid.
* SEV-ES-enabled guest can use from 1 to min_sev_asid - 1.
- * Note: min ASID can end up larger than the max if basic SEV support is
- * effectively disabled by disallowing use of ASIDs for SEV guests.
*/
- unsigned int min_asid = sev->es_active ? 1 : min_sev_asid;
- unsigned int max_asid = sev->es_active ? min_sev_asid - 1 : max_sev_asid;
- unsigned int asid;
+ unsigned int min_asid, max_asid, asid;
bool retry = true;
int ret;
+ if (vm_type == KVM_X86_SNP_VM) {
+ min_asid = min_snp_asid;
+ max_asid = max_snp_asid;
+ } else if (sev->es_active) {
+ min_asid = min_sev_es_asid;
+ max_asid = max_sev_es_asid;
+ } else {
+ min_asid = min_sev_asid;
+ max_asid = max_sev_asid;
+ }
+
+ /*
+ * The min ASID can end up larger than the max if basic SEV support is
+ * effectively disabled by disallowing use of ASIDs for SEV guests.
+ * Similarly for SEV-ES guests the min ASID can end up larger than the
+ * max when ciphertext hiding is enabled, effectively disabling SEV-ES
+ * support.
+ */
if (min_asid > max_asid)
return -ENOTTY;
@@ -454,7 +475,7 @@ static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp,
if (snp_active)
sev->vmsa_features |= SVM_SEV_FEAT_SNP_ACTIVE;
- ret = sev_asid_new(sev);
+ ret = sev_asid_new(sev, vm_type);
if (ret)
goto e_no_asid;
@@ -3058,6 +3079,9 @@ void __init sev_hardware_setup(void)
if (min_sev_asid == 1)
goto out;
+ min_sev_es_asid = min_snp_asid = 1;
+ max_sev_es_asid = max_snp_asid = min_sev_asid - 1;
+
sev_es_asid_count = min_sev_asid - 1;
WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count));
sev_es_supported = true;
@@ -3066,10 +3090,32 @@ void __init sev_hardware_setup(void)
out:
if (sev_enabled) {
init_args.probe = true;
+
+ if (sev_is_snp_ciphertext_hiding_supported())
+ init_args.max_snp_asid = min(nr_ciphertext_hiding_asids,
+ min_sev_asid - 1);
+
if (sev_platform_init(&init_args))
sev_supported = sev_es_supported = sev_snp_supported = false;
else if (sev_snp_supported)
sev_snp_supported = is_sev_snp_initialized();
+
+ if (sev_snp_supported)
+ nr_ciphertext_hiding_asids = init_args.max_snp_asid;
+
+ /*
+ * If ciphertext hiding is enabled, the joint SEV-ES/SEV-SNP
+ * ASID range is partitioned into separate SEV-ES and SEV-SNP
+ * ASID ranges, with the SEV-SNP range being [1..max_snp_asid]
+ * and the SEV-ES range being (max_snp_asid..max_sev_es_asid].
+ * Note, SEV-ES may effectively be disabled if all ASIDs from
+ * the joint range are assigned to SEV-SNP.
+ */
+ if (nr_ciphertext_hiding_asids) {
+ max_snp_asid = nr_ciphertext_hiding_asids;
+ min_sev_es_asid = max_snp_asid + 1;
+ pr_info("SEV-SNP ciphertext hiding enabled\n");
+ }
}
if (boot_cpu_has(X86_FEATURE_SEV))
@@ -3080,12 +3126,14 @@ out:
min_sev_asid, max_sev_asid);
if (boot_cpu_has(X86_FEATURE_SEV_ES))
pr_info("SEV-ES %s (ASIDs %u - %u)\n",
- str_enabled_disabled(sev_es_supported),
- min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
+ sev_es_supported ? min_sev_es_asid <= max_sev_es_asid ? "enabled" :
+ "unusable" :
+ "disabled",
+ min_sev_es_asid, max_sev_es_asid);
if (boot_cpu_has(X86_FEATURE_SEV_SNP))
pr_info("SEV-SNP %s (ASIDs %u - %u)\n",
str_enabled_disabled(sev_snp_supported),
- min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
+ min_snp_asid, max_snp_asid);
sev_enabled = sev_supported;
sev_es_enabled = sev_es_supported;
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 9f5ccc1720cb..011ca31bdd72 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -233,6 +233,7 @@ static int sev_cmd_buffer_len(int cmd)
case SEV_CMD_SNP_GUEST_REQUEST: return sizeof(struct sev_data_snp_guest_request);
case SEV_CMD_SNP_CONFIG: return sizeof(struct sev_user_data_snp_config);
case SEV_CMD_SNP_COMMIT: return sizeof(struct sev_data_snp_commit);
+ case SEV_CMD_SNP_FEATURE_INFO: return sizeof(struct sev_data_snp_feature_info);
default: return 0;
}
@@ -1073,6 +1074,88 @@ static void snp_set_hsave_pa(void *arg)
wrmsrq(MSR_VM_HSAVE_PA, 0);
}
+bool sev_is_snp_ciphertext_hiding_supported(void)
+{
+ struct psp_device *psp = psp_master;
+ struct sev_device *sev;
+
+ if (!psp || !psp->sev_data)
+ return false;
+
+ sev = psp->sev_data;
+
+ /*
+ * Feature information indicates if CipherTextHiding feature is
+ * supported by the SEV firmware and additionally platform status
+ * indicates if CipherTextHiding feature is enabled in the
+ * Platform BIOS.
+ */
+ return ((sev->snp_feat_info_0.ecx & SNP_CIPHER_TEXT_HIDING_SUPPORTED) &&
+ sev->snp_plat_status.ciphertext_hiding_cap);
+}
+EXPORT_SYMBOL_GPL(sev_is_snp_ciphertext_hiding_supported);
+
+static int snp_get_platform_data(struct sev_device *sev, int *error)
+{
+ struct sev_data_snp_feature_info snp_feat_info;
+ struct snp_feature_info *feat_info;
+ struct sev_data_snp_addr buf;
+ struct page *page;
+ int rc;
+
+ /*
+ * This function is expected to be called before SNP is
+ * initialized.
+ */
+ if (sev->snp_initialized)
+ return -EINVAL;
+
+ buf.address = __psp_pa(&sev->snp_plat_status);
+ rc = sev_do_cmd(SEV_CMD_SNP_PLATFORM_STATUS, &buf, error);
+ if (rc) {
+ dev_err(sev->dev, "SNP PLATFORM_STATUS command failed, ret = %d, error = %#x\n",
+ rc, *error);
+ return rc;
+ }
+
+ sev->api_major = sev->snp_plat_status.api_major;
+ sev->api_minor = sev->snp_plat_status.api_minor;
+ sev->build = sev->snp_plat_status.build_id;
+
+ /*
+ * Do feature discovery of the currently loaded firmware,
+ * and cache feature information from CPUID 0x8000_0024,
+ * sub-function 0.
+ */
+ if (!sev->snp_plat_status.feature_info)
+ return 0;
+
+ /*
+ * Use dynamically allocated structure for the SNP_FEATURE_INFO
+ * command to ensure structure is 8-byte aligned, and does not
+ * cross a page boundary.
+ */
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return -ENOMEM;
+
+ feat_info = page_address(page);
+ snp_feat_info.length = sizeof(snp_feat_info);
+ snp_feat_info.ecx_in = 0;
+ snp_feat_info.feature_info_paddr = __psp_pa(feat_info);
+
+ rc = sev_do_cmd(SEV_CMD_SNP_FEATURE_INFO, &snp_feat_info, error);
+ if (!rc)
+ sev->snp_feat_info_0 = *feat_info;
+ else
+ dev_err(sev->dev, "SNP FEATURE_INFO command failed, ret = %d, error = %#x\n",
+ rc, *error);
+
+ __free_page(page);
+
+ return rc;
+}
+
static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
{
struct sev_data_range_list *range_list = arg;
@@ -1103,7 +1186,7 @@ static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
return 0;
}
-static int __sev_snp_init_locked(int *error)
+static int __sev_snp_init_locked(int *error, unsigned int max_snp_asid)
{
struct psp_device *psp = psp_master;
struct sev_data_snp_init_ex data;
@@ -1164,6 +1247,12 @@ static int __sev_snp_init_locked(int *error)
}
memset(&data, 0, sizeof(data));
+
+ if (max_snp_asid) {
+ data.ciphertext_hiding_en = 1;
+ data.max_snp_asid = max_snp_asid;
+ }
+
data.init_rmp = 1;
data.list_paddr_en = 1;
data.list_paddr = __psp_pa(snp_range_list);
@@ -1286,7 +1375,7 @@ static int __sev_platform_init_locked(int *error)
sev = psp_master->sev_data;
- if (sev->state == SEV_STATE_INIT)
+ if (sev->sev_plat_status.state == SEV_STATE_INIT)
return 0;
__sev_platform_init_handle_tmr(sev);
@@ -1318,7 +1407,7 @@ static int __sev_platform_init_locked(int *error)
return rc;
}
- sev->state = SEV_STATE_INIT;
+ sev->sev_plat_status.state = SEV_STATE_INIT;
/* Prepare for first SEV guest launch after INIT */
wbinvd_on_all_cpus();
@@ -1347,10 +1436,10 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
sev = psp_master->sev_data;
- if (sev->state == SEV_STATE_INIT)
+ if (sev->sev_plat_status.state == SEV_STATE_INIT)
return 0;
- rc = __sev_snp_init_locked(&args->error);
+ rc = __sev_snp_init_locked(&args->error, args->max_snp_asid);
if (rc && rc != -ENODEV)
return rc;
@@ -1384,7 +1473,7 @@ static int __sev_platform_shutdown_locked(int *error)
sev = psp->sev_data;
- if (sev->state == SEV_STATE_UNINIT)
+ if (sev->sev_plat_status.state == SEV_STATE_UNINIT)
return 0;
ret = __sev_do_cmd_locked(SEV_CMD_SHUTDOWN, NULL, error);
@@ -1394,7 +1483,7 @@ static int __sev_platform_shutdown_locked(int *error)
return ret;
}
- sev->state = SEV_STATE_UNINIT;
+ sev->sev_plat_status.state = SEV_STATE_UNINIT;
dev_dbg(sev->dev, "SEV firmware shutdown\n");
return ret;
@@ -1433,7 +1522,7 @@ static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req
{
int error, rc;
- rc = __sev_snp_init_locked(&error);
+ rc = __sev_snp_init_locked(&error, 0);
if (rc) {
argp->error = SEV_RET_INVALID_PLATFORM_STATE;
return rc;
@@ -1502,7 +1591,7 @@ static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp, bool wr
if (!writable)
return -EPERM;
- if (sev->state == SEV_STATE_UNINIT) {
+ if (sev->sev_plat_status.state == SEV_STATE_UNINIT) {
rc = sev_move_to_init_state(argp, &shutdown_required);
if (rc)
return rc;
@@ -1551,7 +1640,7 @@ static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp, bool writable)
data.len = input.length;
cmd:
- if (sev->state == SEV_STATE_UNINIT) {
+ if (sev->sev_plat_status.state == SEV_STATE_UNINIT) {
ret = sev_move_to_init_state(argp, &shutdown_required);
if (ret)
goto e_free_blob;
@@ -1599,6 +1688,16 @@ static int sev_get_api_version(void)
struct sev_user_data_status status;
int error = 0, ret;
+ /*
+ * Cache SNP platform status and SNP feature information
+ * if SNP is available.
+ */
+ if (cc_platform_has(CC_ATTR_HOST_SEV_SNP)) {
+ ret = snp_get_platform_data(sev, &error);
+ if (ret)
+ return 1;
+ }
+
ret = sev_platform_status(&status, &error);
if (ret) {
dev_err(sev->dev,
@@ -1606,10 +1705,12 @@ static int sev_get_api_version(void)
return 1;
}
+ /* Cache SEV platform status */
+ sev->sev_plat_status = status;
+
sev->api_major = status.api_major;
sev->api_minor = status.api_minor;
sev->build = status.build;
- sev->state = status.state;
return 0;
}
@@ -1837,7 +1938,7 @@ static int sev_ioctl_do_pek_import(struct sev_issue_cmd *argp, bool writable)
data.oca_cert_len = input.oca_cert_len;
/* If platform is not in INIT state then transition it to INIT */
- if (sev->state != SEV_STATE_INIT) {
+ if (sev->sev_plat_status.state != SEV_STATE_INIT) {
ret = sev_move_to_init_state(argp, &shutdown_required);
if (ret)
goto e_free_oca;
@@ -2008,7 +2109,7 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd *argp, bool writable)
cmd:
/* If platform is not in INIT state then transition it to INIT. */
- if (sev->state != SEV_STATE_INIT) {
+ if (sev->sev_plat_status.state != SEV_STATE_INIT) {
if (!writable) {
ret = -EPERM;
goto e_free_cert;
diff --git a/drivers/crypto/ccp/sev-dev.h b/drivers/crypto/ccp/sev-dev.h
index 3e4e5574e88a..5aed2595c9ae 100644
--- a/drivers/crypto/ccp/sev-dev.h
+++ b/drivers/crypto/ccp/sev-dev.h
@@ -42,7 +42,6 @@ struct sev_device {
struct sev_vdata *vdata;
- int state;
unsigned int int_rcvd;
wait_queue_head_t int_queue;
struct sev_misc_dev *misc;
@@ -57,6 +56,11 @@ struct sev_device {
bool cmd_buf_backup_active;
bool snp_initialized;
+
+ struct sev_user_data_status sev_plat_status;
+
+ struct sev_user_data_snp_status snp_plat_status;
+ struct snp_feature_info snp_feat_info_0;
};
int sev_dev_init(struct psp_device *psp);
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index 0f5f94137f6d..e0dbcb4b4fd9 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -107,6 +107,7 @@ enum sev_cmd {
SEV_CMD_SNP_DOWNLOAD_FIRMWARE_EX = 0x0CA,
SEV_CMD_SNP_COMMIT = 0x0CB,
SEV_CMD_SNP_VLEK_LOAD = 0x0CD,
+ SEV_CMD_SNP_FEATURE_INFO = 0x0CE,
SEV_CMD_MAX,
};
@@ -747,10 +748,13 @@ struct sev_data_snp_guest_request {
struct sev_data_snp_init_ex {
u32 init_rmp:1;
u32 list_paddr_en:1;
- u32 rsvd:30;
+ u32 rapl_dis:1;
+ u32 ciphertext_hiding_en:1;
+ u32 rsvd:28;
u32 rsvd1;
u64 list_paddr;
- u8 rsvd2[48];
+ u16 max_snp_asid;
+ u8 rsvd2[46];
} __packed;
/**
@@ -799,10 +803,13 @@ struct sev_data_snp_shutdown_ex {
* @probe: True if this is being called as part of CCP module probe, which
* will defer SEV_INIT/SEV_INIT_EX firmware initialization until needed
* unless psp_init_on_probe module param is set
+ * @max_snp_asid: When non-zero, enable ciphertext hiding and specify the
+ * maximum ASID that can be used for an SEV-SNP guest.
*/
struct sev_platform_init_args {
int error;
bool probe;
+ unsigned int max_snp_asid;
};
/**
@@ -814,6 +821,36 @@ struct sev_data_snp_commit {
u32 len;
} __packed;
+/**
+ * struct sev_data_snp_feature_info - SEV_SNP_FEATURE_INFO structure
+ *
+ * @length: len of the command buffer read by the PSP
+ * @ecx_in: subfunction index
+ * @feature_info_paddr : System Physical Address of the FEATURE_INFO structure
+ */
+struct sev_data_snp_feature_info {
+ u32 length;
+ u32 ecx_in;
+ u64 feature_info_paddr;
+} __packed;
+
+/**
+ * struct feature_info - FEATURE_INFO structure
+ *
+ * @eax: output of SNP_FEATURE_INFO command
+ * @ebx: output of SNP_FEATURE_INFO command
+ * @ecx: output of SNP_FEATURE_INFO command
+ * #edx: output of SNP_FEATURE_INFO command
+ */
+struct snp_feature_info {
+ u32 eax;
+ u32 ebx;
+ u32 ecx;
+ u32 edx;
+} __packed;
+
+#define SNP_CIPHER_TEXT_HIDING_SUPPORTED BIT(3)
+
#ifdef CONFIG_CRYPTO_DEV_SP_PSP
/**
@@ -957,6 +994,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len);
void *snp_alloc_firmware_page(gfp_t mask);
void snp_free_firmware_page(void *addr);
void sev_platform_shutdown(void);
+bool sev_is_snp_ciphertext_hiding_supported(void);
#else /* !CONFIG_CRYPTO_DEV_SP_PSP */
@@ -993,6 +1031,8 @@ static inline void snp_free_firmware_page(void *addr) { }
static inline void sev_platform_shutdown(void) { }
+static inline bool sev_is_snp_ciphertext_hiding_supported(void) { return false; }
+
#endif /* CONFIG_CRYPTO_DEV_SP_PSP */
#endif /* __PSP_SEV_H__ */
diff --git a/include/uapi/linux/psp-sev.h b/include/uapi/linux/psp-sev.h
index eeb20dfb1fda..c2fd324623c4 100644
--- a/include/uapi/linux/psp-sev.h
+++ b/include/uapi/linux/psp-sev.h
@@ -185,6 +185,10 @@ struct sev_user_data_get_id2 {
* @mask_chip_id: whether chip id is present in attestation reports or not
* @mask_chip_key: whether attestation reports are signed or not
* @vlek_en: VLEK (Version Loaded Endorsement Key) hashstick is loaded
+ * @feature_info: whether SNP_FEATURE_INFO command is available
+ * @rapl_dis: whether RAPL is disabled
+ * @ciphertext_hiding_cap: whether platform has ciphertext hiding capability
+ * @ciphertext_hiding_en: whether ciphertext hiding is enabled
* @rsvd1: reserved
* @guest_count: the number of guest currently managed by the firmware
* @current_tcb_version: current TCB version
@@ -200,7 +204,11 @@ struct sev_user_data_snp_status {
__u32 mask_chip_id:1; /* Out */
__u32 mask_chip_key:1; /* Out */
__u32 vlek_en:1; /* Out */
- __u32 rsvd1:29;
+ __u32 feature_info:1; /* Out */
+ __u32 rapl_dis:1; /* Out */
+ __u32 ciphertext_hiding_cap:1; /* Out */
+ __u32 ciphertext_hiding_en:1; /* Out */
+ __u32 rsvd1:25;
__u32 guest_count; /* Out */
__u64 current_tcb_version; /* Out */
__u64 reported_tcb_version; /* Out */
generated by cgit (git 2.34.1) at 2025-10-17 03:26:40 +0000