Merge tag 'x86-urgent-2024-04-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
- Fix MCE timer reinit locking
- Fix/improve CoCo guest random entropy pool init
- Fix SEV-SNP late disable bugs
- Fix false positive objtool build warning
- Fix header dependency bug
- Fix resctrl CPU offlining bug
* tag 'x86-urgent-2024-04-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/retpoline: Add NOENDBR annotation to the SRSO dummy return thunk
x86/mce: Make sure to grab mce_sysfs_mutex in set_bank()
x86/CPU/AMD: Track SNP host status with cc_platform_*()
x86/cc: Add cc_platform_set/_clear() helpers
x86/kvm/Kconfig: Have KVM_AMD_SEV select ARCH_HAS_CC_PLATFORM
x86/coco: Require seeding RNG with RDRAND on CoCo systems
x86/numa/32: Include missing <asm/pgtable_areas.h>
x86/resctrl: Fix uninitialized memory read when last CPU of domain goes offline
diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c
index d07be9d..b31ef24 100644
--- a/arch/x86/coco/core.c
+++ b/arch/x86/coco/core.c
@@ -3,19 +3,28 @@
* Confidential Computing Platform Capability checks
*
* Copyright (C) 2021 Advanced Micro Devices, Inc.
+ * Copyright (C) 2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*
* Author: Tom Lendacky <thomas.lendacky@amd.com>
*/
#include <linux/export.h>
#include <linux/cc_platform.h>
+#include <linux/string.h>
+#include <linux/random.h>
+#include <asm/archrandom.h>
#include <asm/coco.h>
#include <asm/processor.h>
enum cc_vendor cc_vendor __ro_after_init = CC_VENDOR_NONE;
u64 cc_mask __ro_after_init;
+static struct cc_attr_flags {
+ __u64 host_sev_snp : 1,
+ __resv : 63;
+} cc_flags;
+
static bool noinstr intel_cc_platform_has(enum cc_attr attr)
{
switch (attr) {
@@ -89,6 +98,9 @@
case CC_ATTR_GUEST_SEV_SNP:
return sev_status & MSR_AMD64_SEV_SNP_ENABLED;
+ case CC_ATTR_HOST_SEV_SNP:
+ return cc_flags.host_sev_snp;
+
default:
return false;
}
@@ -148,3 +160,84 @@
}
}
EXPORT_SYMBOL_GPL(cc_mkdec);
+
+static void amd_cc_platform_clear(enum cc_attr attr)
+{
+ switch (attr) {
+ case CC_ATTR_HOST_SEV_SNP:
+ cc_flags.host_sev_snp = 0;
+ break;
+ default:
+ break;
+ }
+}
+
+void cc_platform_clear(enum cc_attr attr)
+{
+ switch (cc_vendor) {
+ case CC_VENDOR_AMD:
+ amd_cc_platform_clear(attr);
+ break;
+ default:
+ break;
+ }
+}
+
+static void amd_cc_platform_set(enum cc_attr attr)
+{
+ switch (attr) {
+ case CC_ATTR_HOST_SEV_SNP:
+ cc_flags.host_sev_snp = 1;
+ break;
+ default:
+ break;
+ }
+}
+
+void cc_platform_set(enum cc_attr attr)
+{
+ switch (cc_vendor) {
+ case CC_VENDOR_AMD:
+ amd_cc_platform_set(attr);
+ break;
+ default:
+ break;
+ }
+}
+
+__init void cc_random_init(void)
+{
+ /*
+ * The seed is 32 bytes (in units of longs), which is 256 bits, which
+ * is the security level that the RNG is targeting.
+ */
+ unsigned long rng_seed[32 / sizeof(long)];
+ size_t i, longs;
+
+ if (!cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT))
+ return;
+
+ /*
+ * Since the CoCo threat model includes the host, the only reliable
+ * source of entropy that can be neither observed nor manipulated is
+ * RDRAND. Usually, RDRAND failure is considered tolerable, but since
+ * CoCo guests have no other unobservable source of entropy, it's
+ * important to at least ensure the RNG gets some initial random seeds.
+ */
+ for (i = 0; i < ARRAY_SIZE(rng_seed); i += longs) {
+ longs = arch_get_random_longs(&rng_seed[i], ARRAY_SIZE(rng_seed) - i);
+
+ /*
+ * A zero return value means that the guest doesn't have RDRAND
+ * or the CPU is physically broken, and in both cases that
+ * means most crypto inside of the CoCo instance will be
+ * broken, defeating the purpose of CoCo in the first place. So
+ * just panic here because it's absolutely unsafe to continue
+ * executing.
+ */
+ if (longs == 0)
+ panic("RDRAND is defective.");
+ }
+ add_device_randomness(rng_seed, sizeof(rng_seed));
+ memzero_explicit(rng_seed, sizeof(rng_seed));
+}
diff --git a/arch/x86/include/asm/coco.h b/arch/x86/include/asm/coco.h
index fb7388b..c086699 100644
--- a/arch/x86/include/asm/coco.h
+++ b/arch/x86/include/asm/coco.h
@@ -22,6 +22,7 @@
u64 cc_mkenc(u64 val);
u64 cc_mkdec(u64 val);
+void cc_random_init(void);
#else
#define cc_vendor (CC_VENDOR_NONE)
@@ -34,6 +35,7 @@
{
return val;
}
+static inline void cc_random_init(void) { }
#endif
#endif /* _ASM_X86_COCO_H */
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 07e125f..7f57382 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -228,7 +228,6 @@
void snp_accept_memory(phys_addr_t start, phys_addr_t end);
u64 snp_get_unsupported_features(u64 status);
u64 sev_get_status(void);
-void kdump_sev_callback(void);
void sev_show_status(void);
#else
static inline void sev_es_ist_enter(struct pt_regs *regs) { }
@@ -258,7 +257,6 @@
static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
static inline u64 sev_get_status(void) { return 0; }
-static inline void kdump_sev_callback(void) { }
static inline void sev_show_status(void) { }
#endif
@@ -270,6 +268,7 @@
int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, u32 asid, bool immutable);
int rmp_make_shared(u64 pfn, enum pg_level level);
void snp_leak_pages(u64 pfn, unsigned int npages);
+void kdump_sev_callback(void);
#else
static inline bool snp_probe_rmptable_info(void) { return false; }
static inline int snp_lookup_rmpentry(u64 pfn, bool *assigned, int *level) { return -ENODEV; }
@@ -282,6 +281,7 @@
}
static inline int rmp_make_shared(u64 pfn, enum pg_level level) { return -ENODEV; }
static inline void snp_leak_pages(u64 pfn, unsigned int npages) {}
+static inline void kdump_sev_callback(void) { }
#endif
#endif
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 6d8677e..9bf17c9 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -345,6 +345,28 @@
#endif
}
+static void bsp_determine_snp(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_ARCH_HAS_CC_PLATFORM
+ cc_vendor = CC_VENDOR_AMD;
+
+ if (cpu_has(c, X86_FEATURE_SEV_SNP)) {
+ /*
+ * RMP table entry format is not architectural and is defined by the
+ * per-processor PPR. Restrict SNP support on the known CPU models
+ * for which the RMP table entry format is currently defined for.
+ */
+ if (!cpu_has(c, X86_FEATURE_HYPERVISOR) &&
+ c->x86 >= 0x19 && snp_probe_rmptable_info()) {
+ cc_platform_set(CC_ATTR_HOST_SEV_SNP);
+ } else {
+ setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
+ cc_platform_clear(CC_ATTR_HOST_SEV_SNP);
+ }
+ }
+#endif
+}
+
static void bsp_init_amd(struct cpuinfo_x86 *c)
{
if (cpu_has(c, X86_FEATURE_CONSTANT_TSC)) {
@@ -452,21 +474,7 @@
break;
}
- if (cpu_has(c, X86_FEATURE_SEV_SNP)) {
- /*
- * RMP table entry format is not architectural and it can vary by processor
- * and is defined by the per-processor PPR. Restrict SNP support on the
- * known CPU model and family for which the RMP table entry format is
- * currently defined for.
- */
- if (!boot_cpu_has(X86_FEATURE_ZEN3) &&
- !boot_cpu_has(X86_FEATURE_ZEN4) &&
- !boot_cpu_has(X86_FEATURE_ZEN5))
- setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
- else if (!snp_probe_rmptable_info())
- setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
- }
-
+ bsp_determine_snp(c);
return;
warn:
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index b5cc557..84d41be 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -2500,12 +2500,14 @@
return -EINVAL;
b = &per_cpu(mce_banks_array, s->id)[bank];
-
if (!b->init)
return -ENODEV;
b->ctl = new;
+
+ mutex_lock(&mce_sysfs_mutex);
mce_restart();
+ mutex_unlock(&mce_sysfs_mutex);
return size;
}
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 422a4dd..7b29ebd 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -108,7 +108,7 @@
(boot_cpu_data.x86 >= 0x0f)))
return;
- if (cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return;
rdmsr(MSR_AMD64_SYSCFG, lo, hi);
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index c99f26e..1a8687f 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -78,7 +78,8 @@
else
cpu = cpumask_any_but(mask, exclude_cpu);
- if (!IS_ENABLED(CONFIG_NO_HZ_FULL))
+ /* Only continue if tick_nohz_full_mask has been initialized. */
+ if (!tick_nohz_full_enabled())
return cpu;
/* If the CPU picked isn't marked nohz_full nothing more needs doing. */
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 0109e6c..e125e05 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -35,6 +35,7 @@
#include <asm/bios_ebda.h>
#include <asm/bugs.h>
#include <asm/cacheinfo.h>
+#include <asm/coco.h>
#include <asm/cpu.h>
#include <asm/efi.h>
#include <asm/gart.h>
@@ -991,6 +992,7 @@
* memory size.
*/
mem_encrypt_setup_arch();
+ cc_random_init();
efi_fake_memmap();
efi_find_mirror();
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
index 7e1e63cc..38ad066 100644
--- a/arch/x86/kernel/sev.c
+++ b/arch/x86/kernel/sev.c
@@ -2284,16 +2284,6 @@
}
device_initcall(snp_init_platform_device);
-void kdump_sev_callback(void)
-{
- /*
- * Do wbinvd() on remote CPUs when SNP is enabled in order to
- * safely do SNP_SHUTDOWN on the local CPU.
- */
- if (cpu_feature_enabled(X86_FEATURE_SEV_SNP))
- wbinvd();
-}
-
void sev_show_status(void)
{
int i;
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index 3aaf7e8..0ebdd08 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -122,6 +122,7 @@
default y
depends on KVM_AMD && X86_64
depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
+ select ARCH_HAS_CC_PLATFORM
help
Provides support for launching Encrypted VMs (SEV) and Encrypted VMs
with Encrypted State (SEV-ES) on AMD processors.
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index e5a4d9b..61a7531 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3184,7 +3184,7 @@
unsigned long pfn;
struct page *p;
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return alloc_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
/*
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index 0795b34..e674ccf 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -229,6 +229,7 @@
/* Dummy for the alternative in CALL_UNTRAIN_RET. */
SYM_CODE_START(srso_alias_untrain_ret)
ANNOTATE_UNRET_SAFE
+ ANNOTATE_NOENDBR
ret
int3
SYM_FUNC_END(srso_alias_untrain_ret)
diff --git a/arch/x86/mm/numa_32.c b/arch/x86/mm/numa_32.c
index 1045443..025fd7e 100644
--- a/arch/x86/mm/numa_32.c
+++ b/arch/x86/mm/numa_32.c
@@ -24,6 +24,7 @@
#include <linux/memblock.h>
#include <linux/init.h>
+#include <asm/pgtable_areas.h>
#include "numa_internal.h"
diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c
index cffe115..ab0e844 100644
--- a/arch/x86/virt/svm/sev.c
+++ b/arch/x86/virt/svm/sev.c
@@ -77,7 +77,7 @@
{
u64 val;
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return 0;
rdmsrl(MSR_AMD64_SYSCFG, val);
@@ -98,7 +98,7 @@
{
u64 val;
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return 0;
rdmsrl(MSR_AMD64_SYSCFG, val);
@@ -174,11 +174,11 @@
u64 rmptable_size;
u64 val;
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return 0;
if (!amd_iommu_snp_en)
- return 0;
+ goto nosnp;
if (!probed_rmp_size)
goto nosnp;
@@ -225,7 +225,7 @@
return 0;
nosnp:
- setup_clear_cpu_cap(X86_FEATURE_SEV_SNP);
+ cc_platform_clear(CC_ATTR_HOST_SEV_SNP);
return -ENOSYS;
}
@@ -246,7 +246,7 @@
{
struct rmpentry *large_entry, *entry;
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return ERR_PTR(-ENODEV);
entry = get_rmpentry(pfn);
@@ -363,7 +363,7 @@
unsigned long paddr = pfn << PAGE_SHIFT;
int ret;
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return -ENODEV;
if (!pfn_valid(pfn))
@@ -472,7 +472,7 @@
unsigned long paddr = pfn << PAGE_SHIFT;
int ret, level;
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return -ENODEV;
level = RMP_TO_PG_LEVEL(state->pagesize);
@@ -558,3 +558,13 @@
spin_unlock(&snp_leaked_pages_list_lock);
}
EXPORT_SYMBOL_GPL(snp_leak_pages);
+
+void kdump_sev_callback(void)
+{
+ /*
+ * Do wbinvd() on remote CPUs when SNP is enabled in order to
+ * safely do SNP_SHUTDOWN on the local CPU.
+ */
+ if (cc_platform_has(CC_ATTR_HOST_SEV_SNP))
+ wbinvd();
+}
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index f44efbb..2102377 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1090,7 +1090,7 @@
void *arg = &data;
int cmd, rc = 0;
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return -ENODEV;
sev = psp->sev_data;
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index e7a4492..33228c1 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -3228,7 +3228,7 @@
static void iommu_snp_enable(void)
{
#ifdef CONFIG_KVM_AMD_SEV
- if (!cpu_feature_enabled(X86_FEATURE_SEV_SNP))
+ if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP))
return;
/*
* The SNP support requires that IOMMU must be enabled, and is
@@ -3236,12 +3236,14 @@
*/
if (no_iommu || iommu_default_passthrough()) {
pr_err("SNP: IOMMU disabled or configured in passthrough mode, SNP cannot be supported.\n");
+ cc_platform_clear(CC_ATTR_HOST_SEV_SNP);
return;
}
amd_iommu_snp_en = check_feature(FEATURE_SNP);
if (!amd_iommu_snp_en) {
pr_err("SNP: IOMMU SNP feature not enabled, SNP cannot be supported.\n");
+ cc_platform_clear(CC_ATTR_HOST_SEV_SNP);
return;
}
diff --git a/include/linux/cc_platform.h b/include/linux/cc_platform.h
index cb0d6cd..60693a1 100644
--- a/include/linux/cc_platform.h
+++ b/include/linux/cc_platform.h
@@ -90,6 +90,14 @@
* Examples include TDX Guest.
*/
CC_ATTR_HOTPLUG_DISABLED,
+
+ /**
+ * @CC_ATTR_HOST_SEV_SNP: AMD SNP enabled on the host.
+ *
+ * The host kernel is running with the necessary features
+ * enabled to run SEV-SNP guests.
+ */
+ CC_ATTR_HOST_SEV_SNP,
};
#ifdef CONFIG_ARCH_HAS_CC_PLATFORM
@@ -107,10 +115,14 @@
* * FALSE - Specified Confidential Computing attribute is not active
*/
bool cc_platform_has(enum cc_attr attr);
+void cc_platform_set(enum cc_attr attr);
+void cc_platform_clear(enum cc_attr attr);
#else /* !CONFIG_ARCH_HAS_CC_PLATFORM */
static inline bool cc_platform_has(enum cc_attr attr) { return false; }
+static inline void cc_platform_set(enum cc_attr attr) { }
+static inline void cc_platform_clear(enum cc_attr attr) { }
#endif /* CONFIG_ARCH_HAS_CC_PLATFORM */
