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-rw-r--r--arch/riscv/boot/dts/thead/th1520.dtsi10
-rw-r--r--arch/x86/boot/cpuflags.c13
-rw-r--r--arch/x86/boot/startup/sev-shared.c8
-rw-r--r--arch/x86/coco/sev/core.c23
-rw-r--r--arch/x86/coco/sev/vc-handle.c31
-rw-r--r--arch/x86/include/asm/cpufeatures.h1
-rw-r--r--arch/x86/include/asm/cpuid.h8
-rw-r--r--arch/x86/include/asm/sev.h19
-rw-r--r--arch/x86/kernel/cpu/bugs.c13
-rw-r--r--arch/x86/kernel/cpu/scattered.c1
-rw-r--r--arch/x86/kernel/fpu/xstate.c19
11 files changed, 108 insertions, 38 deletions
diff --git a/arch/riscv/boot/dts/thead/th1520.dtsi b/arch/riscv/boot/dts/thead/th1520.dtsi
index 42724bf7e90e..03f1d7319049 100644
--- a/arch/riscv/boot/dts/thead/th1520.dtsi
+++ b/arch/riscv/boot/dts/thead/th1520.dtsi
@@ -297,8 +297,9 @@
reg-names = "dwmac", "apb";
interrupts = <67 IRQ_TYPE_LEVEL_HIGH>;
interrupt-names = "macirq";
- clocks = <&clk CLK_GMAC_AXI>, <&clk CLK_GMAC1>;
- clock-names = "stmmaceth", "pclk";
+ clocks = <&clk CLK_GMAC_AXI>, <&clk CLK_GMAC1>,
+ <&clk CLK_PERISYS_APB4_HCLK>;
+ clock-names = "stmmaceth", "pclk", "apb";
snps,pbl = <32>;
snps,fixed-burst;
snps,multicast-filter-bins = <64>;
@@ -319,8 +320,9 @@
reg-names = "dwmac", "apb";
interrupts = <66 IRQ_TYPE_LEVEL_HIGH>;
interrupt-names = "macirq";
- clocks = <&clk CLK_GMAC_AXI>, <&clk CLK_GMAC0>;
- clock-names = "stmmaceth", "pclk";
+ clocks = <&clk CLK_GMAC_AXI>, <&clk CLK_GMAC0>,
+ <&clk CLK_PERISYS_APB4_HCLK>;
+ clock-names = "stmmaceth", "pclk", "apb";
snps,pbl = <32>;
snps,fixed-burst;
snps,multicast-filter-bins = <64>;
diff --git a/arch/x86/boot/cpuflags.c b/arch/x86/boot/cpuflags.c
index 916bac09b464..63e037e94e4c 100644
--- a/arch/x86/boot/cpuflags.c
+++ b/arch/x86/boot/cpuflags.c
@@ -106,5 +106,18 @@ void get_cpuflags(void)
cpuid(0x80000001, &ignored, &ignored, &cpu.flags[6],
&cpu.flags[1]);
}
+
+ if (max_amd_level >= 0x8000001f) {
+ u32 ebx;
+
+ /*
+ * The X86_FEATURE_COHERENCY_SFW_NO feature bit is in
+ * the virtualization flags entry (word 8) and set by
+ * scattered.c, so the bit needs to be explicitly set.
+ */
+ cpuid(0x8000001f, &ignored, &ebx, &ignored, &ignored);
+ if (ebx & BIT(31))
+ set_bit(X86_FEATURE_COHERENCY_SFW_NO, cpu.flags);
+ }
}
}
diff --git a/arch/x86/boot/startup/sev-shared.c b/arch/x86/boot/startup/sev-shared.c
index 7a706db87b93..a34cd19796f9 100644
--- a/arch/x86/boot/startup/sev-shared.c
+++ b/arch/x86/boot/startup/sev-shared.c
@@ -785,6 +785,7 @@ static void __head svsm_pval_4k_page(unsigned long paddr, bool validate)
pc->entry[0].page_size = RMP_PG_SIZE_4K;
pc->entry[0].action = validate;
pc->entry[0].ignore_cf = 0;
+ pc->entry[0].rsvd = 0;
pc->entry[0].pfn = paddr >> PAGE_SHIFT;
/* Protocol 0, Call ID 1 */
@@ -810,6 +811,13 @@ static void __head pvalidate_4k_page(unsigned long vaddr, unsigned long paddr,
if (ret)
sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE);
}
+
+ /*
+ * If validating memory (making it private) and affected by the
+ * cache-coherency vulnerability, perform the cache eviction mitigation.
+ */
+ if (validate && !has_cpuflag(X86_FEATURE_COHERENCY_SFW_NO))
+ sev_evict_cache((void *)vaddr, 1);
}
/*
diff --git a/arch/x86/coco/sev/core.c b/arch/x86/coco/sev/core.c
index fc59ce78c477..14ef5908fb27 100644
--- a/arch/x86/coco/sev/core.c
+++ b/arch/x86/coco/sev/core.c
@@ -227,6 +227,7 @@ static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action,
pe->page_size = RMP_PG_SIZE_4K;
pe->action = action;
pe->ignore_cf = 0;
+ pe->rsvd = 0;
pe->pfn = pfn;
pe++;
@@ -257,6 +258,7 @@ static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int d
pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K;
pe->action = e->operation == SNP_PAGE_STATE_PRIVATE;
pe->ignore_cf = 0;
+ pe->rsvd = 0;
pe->pfn = e->gfn;
pe++;
@@ -358,10 +360,31 @@ static void svsm_pval_pages(struct snp_psc_desc *desc)
static void pvalidate_pages(struct snp_psc_desc *desc)
{
+ struct psc_entry *e;
+ unsigned int i;
+
if (snp_vmpl)
svsm_pval_pages(desc);
else
pval_pages(desc);
+
+ /*
+ * If not affected by the cache-coherency vulnerability there is no need
+ * to perform the cache eviction mitigation.
+ */
+ if (cpu_feature_enabled(X86_FEATURE_COHERENCY_SFW_NO))
+ return;
+
+ for (i = 0; i <= desc->hdr.end_entry; i++) {
+ e = &desc->entries[i];
+
+ /*
+ * If validating memory (making it private) perform the cache
+ * eviction mitigation.
+ */
+ if (e->operation == SNP_PAGE_STATE_PRIVATE)
+ sev_evict_cache(pfn_to_kaddr(e->gfn), e->pagesize ? 512 : 1);
+ }
}
static int vmgexit_psc(struct ghcb *ghcb, struct snp_psc_desc *desc)
diff --git a/arch/x86/coco/sev/vc-handle.c b/arch/x86/coco/sev/vc-handle.c
index faf1fce89ed4..c3b4acbde0d8 100644
--- a/arch/x86/coco/sev/vc-handle.c
+++ b/arch/x86/coco/sev/vc-handle.c
@@ -371,29 +371,30 @@ static enum es_result __vc_handle_msr_caa(struct pt_regs *regs, bool write)
* executing with Secure TSC enabled, so special handling is required for
* accesses of MSR_IA32_TSC and MSR_AMD64_GUEST_TSC_FREQ.
*/
-static enum es_result __vc_handle_secure_tsc_msrs(struct pt_regs *regs, bool write)
+static enum es_result __vc_handle_secure_tsc_msrs(struct es_em_ctxt *ctxt, bool write)
{
+ struct pt_regs *regs = ctxt->regs;
u64 tsc;
/*
- * GUEST_TSC_FREQ should not be intercepted when Secure TSC is enabled.
- * Terminate the SNP guest when the interception is enabled.
+ * Writing to MSR_IA32_TSC can cause subsequent reads of the TSC to
+ * return undefined values, and GUEST_TSC_FREQ is read-only. Generate
+ * a #GP on all writes.
*/
- if (regs->cx == MSR_AMD64_GUEST_TSC_FREQ)
- return ES_VMM_ERROR;
+ if (write) {
+ ctxt->fi.vector = X86_TRAP_GP;
+ ctxt->fi.error_code = 0;
+ return ES_EXCEPTION;
+ }
/*
- * Writes: Writing to MSR_IA32_TSC can cause subsequent reads of the TSC
- * to return undefined values, so ignore all writes.
- *
- * Reads: Reads of MSR_IA32_TSC should return the current TSC value, use
- * the value returned by rdtsc_ordered().
+ * GUEST_TSC_FREQ read should not be intercepted when Secure TSC is
+ * enabled. Terminate the guest if a read is attempted.
*/
- if (write) {
- WARN_ONCE(1, "TSC MSR writes are verboten!\n");
- return ES_OK;
- }
+ if (regs->cx == MSR_AMD64_GUEST_TSC_FREQ)
+ return ES_VMM_ERROR;
+ /* Reads of MSR_IA32_TSC should return the current TSC value. */
tsc = rdtsc_ordered();
regs->ax = lower_32_bits(tsc);
regs->dx = upper_32_bits(tsc);
@@ -416,7 +417,7 @@ static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt)
case MSR_IA32_TSC:
case MSR_AMD64_GUEST_TSC_FREQ:
if (sev_status & MSR_AMD64_SNP_SECURE_TSC)
- return __vc_handle_secure_tsc_msrs(regs, write);
+ return __vc_handle_secure_tsc_msrs(ctxt, write);
break;
default:
break;
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 602957dd2609..06fc0479a23f 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -218,6 +218,7 @@
#define X86_FEATURE_FLEXPRIORITY ( 8*32+ 1) /* "flexpriority" Intel FlexPriority */
#define X86_FEATURE_EPT ( 8*32+ 2) /* "ept" Intel Extended Page Table */
#define X86_FEATURE_VPID ( 8*32+ 3) /* "vpid" Intel Virtual Processor ID */
+#define X86_FEATURE_COHERENCY_SFW_NO ( 8*32+ 4) /* SNP cache coherency software work around not needed */
#define X86_FEATURE_VMMCALL ( 8*32+15) /* "vmmcall" Prefer VMMCALL to VMCALL */
#define X86_FEATURE_XENPV ( 8*32+16) /* Xen paravirtual guest */
diff --git a/arch/x86/include/asm/cpuid.h b/arch/x86/include/asm/cpuid.h
deleted file mode 100644
index d5749b25fa10..000000000000
--- a/arch/x86/include/asm/cpuid.h
+++ /dev/null
@@ -1,8 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-#ifndef _ASM_X86_CPUID_H
-#define _ASM_X86_CPUID_H
-
-#include <asm/cpuid/api.h>
-
-#endif /* _ASM_X86_CPUID_H */
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
index 89075ff19afa..02236962fdb1 100644
--- a/arch/x86/include/asm/sev.h
+++ b/arch/x86/include/asm/sev.h
@@ -619,6 +619,24 @@ int rmp_make_shared(u64 pfn, enum pg_level level);
void snp_leak_pages(u64 pfn, unsigned int npages);
void kdump_sev_callback(void);
void snp_fixup_e820_tables(void);
+
+static inline void sev_evict_cache(void *va, int npages)
+{
+ volatile u8 val __always_unused;
+ u8 *bytes = va;
+ int page_idx;
+
+ /*
+ * For SEV guests, a read from the first/last cache-lines of a 4K page
+ * using the guest key is sufficient to cause a flush of all cache-lines
+ * associated with that 4K page without incurring all the overhead of a
+ * full CLFLUSH sequence.
+ */
+ for (page_idx = 0; page_idx < npages; page_idx++) {
+ val = bytes[page_idx * PAGE_SIZE];
+ val = bytes[page_idx * PAGE_SIZE + PAGE_SIZE - 1];
+ }
+}
#else
static inline bool snp_probe_rmptable_info(void) { return false; }
static inline int snp_rmptable_init(void) { return -ENOSYS; }
@@ -634,6 +652,7 @@ 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) { }
static inline void snp_fixup_e820_tables(void) {}
+static inline void sev_evict_cache(void *va, int npages) {}
#endif
#endif
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index b74bf937cd9f..2186a771b9fc 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -386,7 +386,6 @@ static bool __init should_mitigate_vuln(unsigned int bug)
case X86_BUG_SPECTRE_V2:
case X86_BUG_RETBLEED:
- case X86_BUG_SRSO:
case X86_BUG_L1TF:
case X86_BUG_ITS:
return cpu_attack_vector_mitigated(CPU_MITIGATE_USER_KERNEL) ||
@@ -3184,8 +3183,18 @@ static void __init srso_select_mitigation(void)
}
if (srso_mitigation == SRSO_MITIGATION_AUTO) {
- if (should_mitigate_vuln(X86_BUG_SRSO)) {
+ /*
+ * Use safe-RET if user->kernel or guest->host protection is
+ * required. Otherwise the 'microcode' mitigation is sufficient
+ * to protect the user->user and guest->guest vectors.
+ */
+ if (cpu_attack_vector_mitigated(CPU_MITIGATE_GUEST_HOST) ||
+ (cpu_attack_vector_mitigated(CPU_MITIGATE_USER_KERNEL) &&
+ !boot_cpu_has(X86_FEATURE_SRSO_USER_KERNEL_NO))) {
srso_mitigation = SRSO_MITIGATION_SAFE_RET;
+ } else if (cpu_attack_vector_mitigated(CPU_MITIGATE_USER_USER) ||
+ cpu_attack_vector_mitigated(CPU_MITIGATE_GUEST_GUEST)) {
+ srso_mitigation = SRSO_MITIGATION_MICROCODE;
} else {
srso_mitigation = SRSO_MITIGATION_NONE;
return;
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index b4a1f6732a3a..6b868afb26c3 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -48,6 +48,7 @@ static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
{ X86_FEATURE_AMD_FAST_CPPC, CPUID_EDX, 15, 0x80000007, 0 },
{ X86_FEATURE_MBA, CPUID_EBX, 6, 0x80000008, 0 },
+ { X86_FEATURE_COHERENCY_SFW_NO, CPUID_EBX, 31, 0x8000001f, 0 },
{ X86_FEATURE_SMBA, CPUID_EBX, 2, 0x80000020, 0 },
{ X86_FEATURE_BMEC, CPUID_EBX, 3, 0x80000020, 0 },
{ X86_FEATURE_TSA_SQ_NO, CPUID_ECX, 1, 0x80000021, 0 },
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 12ed75c1b567..28e4fd65c9da 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1881,19 +1881,20 @@ long fpu_xstate_prctl(int option, unsigned long arg2)
#ifdef CONFIG_PROC_PID_ARCH_STATUS
/*
* Report the amount of time elapsed in millisecond since last AVX512
- * use in the task.
+ * use in the task. Report -1 if no AVX-512 usage.
*/
static void avx512_status(struct seq_file *m, struct task_struct *task)
{
- unsigned long timestamp = READ_ONCE(x86_task_fpu(task)->avx512_timestamp);
- long delta;
+ unsigned long timestamp;
+ long delta = -1;
- if (!timestamp) {
- /*
- * Report -1 if no AVX512 usage
- */
- delta = -1;
- } else {
+ /* AVX-512 usage is not tracked for kernel threads. Don't report anything. */
+ if (task->flags & (PF_KTHREAD | PF_USER_WORKER))
+ return;
+
+ timestamp = READ_ONCE(x86_task_fpu(task)->avx512_timestamp);
+
+ if (timestamp) {
delta = (long)(jiffies - timestamp);
/*
* Cap to LONG_MAX if time difference > LONG_MAX
generated by cgit v1.2.3 (git 2.46.0) at 2025-08-18 09:45:20 +0000