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-rw-r--r--arch/x86/boot/cpuflags.c13
-rw-r--r--arch/x86/coco/sev/shared.c46
-rw-r--r--arch/x86/include/asm/cpufeatures.h1
-rw-r--r--arch/x86/include/asm/hw_irq.h12
-rw-r--r--arch/x86/kernel/cpu/scattered.c1
-rw-r--r--arch/x86/kernel/irq.c63
-rw-r--r--arch/x86/mm/extable.c5
7 files changed, 118 insertions, 23 deletions
diff --git a/arch/x86/boot/cpuflags.c b/arch/x86/boot/cpuflags.c
index d75237ba7ce9..5660d3229d29 100644
--- a/arch/x86/boot/cpuflags.c
+++ b/arch/x86/boot/cpuflags.c
@@ -115,5 +115,18 @@ 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/coco/sev/shared.c b/arch/x86/coco/sev/shared.c
index 71de53194089..f5936da235c7 100644
--- a/arch/x86/coco/sev/shared.c
+++ b/arch/x86/coco/sev/shared.c
@@ -1243,6 +1243,24 @@ static void svsm_pval_terminate(struct svsm_pvalidate_call *pc, int ret, u64 svs
__pval_terminate(pfn, action, page_size, ret, svsm_ret);
}
+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];
+ }
+}
+
static void svsm_pval_4k_page(unsigned long paddr, bool validate)
{
struct svsm_pvalidate_call *pc;
@@ -1295,6 +1313,13 @@ static void pvalidate_4k_page(unsigned long vaddr, unsigned long paddr, bool val
if (ret)
__pval_terminate(PHYS_PFN(paddr), validate, RMP_PG_SIZE_4K, ret, 0);
}
+
+ /*
+ * 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);
}
static void pval_pages(struct snp_psc_desc *desc)
@@ -1479,10 +1504,31 @@ 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/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index ef5749a0d8c2..98e72c1391f2 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -227,6 +227,7 @@
#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/hw_irq.h b/arch/x86/include/asm/hw_irq.h
index edebf1020e04..6bb3d9a86abe 100644
--- a/arch/x86/include/asm/hw_irq.h
+++ b/arch/x86/include/asm/hw_irq.h
@@ -92,8 +92,6 @@ struct irq_cfg {
extern struct irq_cfg *irq_cfg(unsigned int irq);
extern struct irq_cfg *irqd_cfg(struct irq_data *irq_data);
-extern void lock_vector_lock(void);
-extern void unlock_vector_lock(void);
#ifdef CONFIG_SMP
extern void vector_schedule_cleanup(struct irq_cfg *);
extern void irq_complete_move(struct irq_cfg *cfg);
@@ -101,12 +99,16 @@ extern void irq_complete_move(struct irq_cfg *cfg);
static inline void vector_schedule_cleanup(struct irq_cfg *c) { }
static inline void irq_complete_move(struct irq_cfg *c) { }
#endif
-
extern void apic_ack_edge(struct irq_data *data);
-#else /* CONFIG_IRQ_DOMAIN_HIERARCHY */
+#endif /* CONFIG_IRQ_DOMAIN_HIERARCHY */
+
+#ifdef CONFIG_X86_LOCAL_APIC
+extern void lock_vector_lock(void);
+extern void unlock_vector_lock(void);
+#else
static inline void lock_vector_lock(void) {}
static inline void unlock_vector_lock(void) {}
-#endif /* CONFIG_IRQ_DOMAIN_HIERARCHY */
+#endif
/* Statistics */
extern atomic_t irq_err_count;
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index bc4993aa41ed..c463363ae1d4 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -47,6 +47,7 @@ static const struct cpuid_bit cpuid_bits[] = {
{ X86_FEATURE_PROC_FEEDBACK, CPUID_EDX, 11, 0x80000007, 0 },
{ X86_FEATURE_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/irq.c b/arch/x86/kernel/irq.c
index 85fa2db38dc4..9400730e538e 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -251,26 +251,59 @@ static __always_inline void handle_irq(struct irq_desc *desc,
__handle_irq(desc, regs);
}
-static __always_inline int call_irq_handler(int vector, struct pt_regs *regs)
+static struct irq_desc *reevaluate_vector(int vector)
{
- struct irq_desc *desc;
- int ret = 0;
+ struct irq_desc *desc = __this_cpu_read(vector_irq[vector]);
+
+ if (!IS_ERR_OR_NULL(desc))
+ return desc;
+
+ if (desc == VECTOR_UNUSED)
+ pr_emerg_ratelimited("No irq handler for %d.%u\n", smp_processor_id(), vector);
+ else
+ __this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
+ return NULL;
+}
+
+static __always_inline bool call_irq_handler(int vector, struct pt_regs *regs)
+{
+ struct irq_desc *desc = __this_cpu_read(vector_irq[vector]);
- desc = __this_cpu_read(vector_irq[vector]);
if (likely(!IS_ERR_OR_NULL(desc))) {
handle_irq(desc, regs);
- } else {
- ret = -EINVAL;
- if (desc == VECTOR_UNUSED) {
- pr_emerg_ratelimited("%s: %d.%u No irq handler for vector\n",
- __func__, smp_processor_id(),
- vector);
- } else {
- __this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
- }
+ return true;
}
- return ret;
+ /*
+ * Reevaluate with vector_lock held to prevent a race against
+ * request_irq() setting up the vector:
+ *
+ * CPU0 CPU1
+ * interrupt is raised in APIC IRR
+ * but not handled
+ * free_irq()
+ * per_cpu(vector_irq, CPU1)[vector] = VECTOR_SHUTDOWN;
+ *
+ * request_irq() common_interrupt()
+ * d = this_cpu_read(vector_irq[vector]);
+ *
+ * per_cpu(vector_irq, CPU1)[vector] = desc;
+ *
+ * if (d == VECTOR_SHUTDOWN)
+ * this_cpu_write(vector_irq[vector], VECTOR_UNUSED);
+ *
+ * This requires that the same vector on the same target CPU is
+ * handed out or that a spurious interrupt hits that CPU/vector.
+ */
+ lock_vector_lock();
+ desc = reevaluate_vector(vector);
+ unlock_vector_lock();
+
+ if (!desc)
+ return false;
+
+ handle_irq(desc, regs);
+ return true;
}
/*
@@ -284,7 +317,7 @@ DEFINE_IDTENTRY_IRQ(common_interrupt)
/* entry code tells RCU that we're not quiescent. Check it. */
RCU_LOCKDEP_WARN(!rcu_is_watching(), "IRQ failed to wake up RCU");
- if (unlikely(call_irq_handler(vector, regs)))
+ if (unlikely(!call_irq_handler(vector, regs)))
apic_eoi();
set_irq_regs(old_regs);
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 51986e8a9d35..52e22d3e1a82 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -122,13 +122,12 @@ static bool ex_handler_sgx(const struct exception_table_entry *fixup,
static bool ex_handler_fprestore(const struct exception_table_entry *fixup,
struct pt_regs *regs)
{
- regs->ip = ex_fixup_addr(fixup);
-
WARN_ONCE(1, "Bad FPU state detected at %pB, reinitializing FPU registers.",
(void *)instruction_pointer(regs));
fpu_reset_from_exception_fixup();
- return true;
+
+ return ex_handler_default(fixup, regs);
}
/*
generated by cgit v1.2.3 (git 2.39.0) at 2025-08-16 12:14:12 +0300