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-rw-r--r--arch/arm64/include/asm/fpsimd.h1
-rw-r--r--arch/arm64/kernel/cpufeature.c2
-rw-r--r--arch/arm64/kernel/fpsimd.c86
3 files changed, 73 insertions, 16 deletions
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index dd1ad3950ef5..964adc9f312d 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -87,6 +87,7 @@ extern void sve_kernel_enable(const struct arm64_cpu_capabilities *__unused);
extern u64 read_zcr_features(void);
extern int __ro_after_init sve_max_vl;
+extern int __ro_after_init sve_max_virtualisable_vl;
#ifdef CONFIG_ARM64_SVE
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 4061de10cea6..7f8cc51f0740 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1863,7 +1863,7 @@ static void verify_sve_features(void)
unsigned int len = zcr & ZCR_ELx_LEN_MASK;
if (len < safe_len || sve_verify_vq_map()) {
- pr_crit("CPU%d: SVE: required vector length(s) missing\n",
+ pr_crit("CPU%d: SVE: vector length support mismatch\n",
smp_processor_id());
cpu_die_early();
}
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index f59ea677cd42..b219796a4081 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -18,6 +18,7 @@
*/
#include <linux/bitmap.h>
+#include <linux/bitops.h>
#include <linux/bottom_half.h>
#include <linux/bug.h>
#include <linux/cache.h>
@@ -48,6 +49,7 @@
#include <asm/sigcontext.h>
#include <asm/sysreg.h>
#include <asm/traps.h>
+#include <asm/virt.h>
#define FPEXC_IOF (1 << 0)
#define FPEXC_DZF (1 << 1)
@@ -130,14 +132,18 @@ static int sve_default_vl = -1;
/* Maximum supported vector length across all CPUs (initially poisoned) */
int __ro_after_init sve_max_vl = SVE_VL_MIN;
+int __ro_after_init sve_max_virtualisable_vl = SVE_VL_MIN;
/* Set of available vector lengths, as vq_to_bit(vq): */
static __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
+/* Set of vector lengths present on at least one cpu: */
+static __ro_after_init DECLARE_BITMAP(sve_vq_partial_map, SVE_VQ_MAX);
static void __percpu *efi_sve_state;
#else /* ! CONFIG_ARM64_SVE */
/* Dummy declaration for code that will be optimised out: */
extern __ro_after_init DECLARE_BITMAP(sve_vq_map, SVE_VQ_MAX);
+extern __ro_after_init DECLARE_BITMAP(sve_vq_partial_map, SVE_VQ_MAX);
extern void __percpu *efi_sve_state;
#endif /* ! CONFIG_ARM64_SVE */
@@ -623,12 +629,6 @@ int sve_get_current_vl(void)
return sve_prctl_status(0);
}
-/*
- * Bitmap for temporary storage of the per-CPU set of supported vector lengths
- * during secondary boot.
- */
-static DECLARE_BITMAP(sve_secondary_vq_map, SVE_VQ_MAX);
-
static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX))
{
unsigned int vq, vl;
@@ -654,6 +654,7 @@ static void sve_probe_vqs(DECLARE_BITMAP(map, SVE_VQ_MAX))
void __init sve_init_vq_map(void)
{
sve_probe_vqs(sve_vq_map);
+ bitmap_copy(sve_vq_partial_map, sve_vq_map, SVE_VQ_MAX);
}
/*
@@ -663,8 +664,11 @@ void __init sve_init_vq_map(void)
*/
void sve_update_vq_map(void)
{
- sve_probe_vqs(sve_secondary_vq_map);
- bitmap_and(sve_vq_map, sve_vq_map, sve_secondary_vq_map, SVE_VQ_MAX);
+ DECLARE_BITMAP(tmp_map, SVE_VQ_MAX);
+
+ sve_probe_vqs(tmp_map);
+ bitmap_and(sve_vq_map, sve_vq_map, tmp_map, SVE_VQ_MAX);
+ bitmap_or(sve_vq_partial_map, sve_vq_partial_map, tmp_map, SVE_VQ_MAX);
}
/*
@@ -673,18 +677,48 @@ void sve_update_vq_map(void)
*/
int sve_verify_vq_map(void)
{
- int ret = 0;
+ DECLARE_BITMAP(tmp_map, SVE_VQ_MAX);
+ unsigned long b;
- sve_probe_vqs(sve_secondary_vq_map);
- bitmap_andnot(sve_secondary_vq_map, sve_vq_map, sve_secondary_vq_map,
- SVE_VQ_MAX);
- if (!bitmap_empty(sve_secondary_vq_map, SVE_VQ_MAX)) {
+ sve_probe_vqs(tmp_map);
+
+ bitmap_complement(tmp_map, tmp_map, SVE_VQ_MAX);
+ if (bitmap_intersects(tmp_map, sve_vq_map, SVE_VQ_MAX)) {
pr_warn("SVE: cpu%d: Required vector length(s) missing\n",
smp_processor_id());
- ret = -EINVAL;
+ return -EINVAL;
}
- return ret;
+ if (!IS_ENABLED(CONFIG_KVM) || !is_hyp_mode_available())
+ return 0;
+
+ /*
+ * For KVM, it is necessary to ensure that this CPU doesn't
+ * support any vector length that guests may have probed as
+ * unsupported.
+ */
+
+ /* Recover the set of supported VQs: */
+ bitmap_complement(tmp_map, tmp_map, SVE_VQ_MAX);
+ /* Find VQs supported that are not globally supported: */
+ bitmap_andnot(tmp_map, tmp_map, sve_vq_map, SVE_VQ_MAX);
+
+ /* Find the lowest such VQ, if any: */
+ b = find_last_bit(tmp_map, SVE_VQ_MAX);
+ if (b >= SVE_VQ_MAX)
+ return 0; /* no mismatches */
+
+ /*
+ * Mismatches above sve_max_virtualisable_vl are fine, since
+ * no guest is allowed to configure ZCR_EL2.LEN to exceed this:
+ */
+ if (sve_vl_from_vq(bit_to_vq(b)) <= sve_max_virtualisable_vl) {
+ pr_warn("SVE: cpu%d: Unsupported vector length(s) present\n",
+ smp_processor_id());
+ return -EINVAL;
+ }
+
+ return 0;
}
static void __init sve_efi_setup(void)
@@ -751,6 +785,8 @@ u64 read_zcr_features(void)
void __init sve_setup(void)
{
u64 zcr;
+ DECLARE_BITMAP(tmp_map, SVE_VQ_MAX);
+ unsigned long b;
if (!system_supports_sve())
return;
@@ -779,11 +815,31 @@ void __init sve_setup(void)
*/
sve_default_vl = find_supported_vector_length(64);
+ bitmap_andnot(tmp_map, sve_vq_partial_map, sve_vq_map,
+ SVE_VQ_MAX);
+
+ b = find_last_bit(tmp_map, SVE_VQ_MAX);
+ if (b >= SVE_VQ_MAX)
+ /* No non-virtualisable VLs found */
+ sve_max_virtualisable_vl = SVE_VQ_MAX;
+ else if (WARN_ON(b == SVE_VQ_MAX - 1))
+ /* No virtualisable VLs? This is architecturally forbidden. */
+ sve_max_virtualisable_vl = SVE_VQ_MIN;
+ else /* b + 1 < SVE_VQ_MAX */
+ sve_max_virtualisable_vl = sve_vl_from_vq(bit_to_vq(b + 1));
+
+ if (sve_max_virtualisable_vl > sve_max_vl)
+ sve_max_virtualisable_vl = sve_max_vl;
+
pr_info("SVE: maximum available vector length %u bytes per vector\n",
sve_max_vl);
pr_info("SVE: default vector length %u bytes per vector\n",
sve_default_vl);
+ /* KVM decides whether to support mismatched systems. Just warn here: */
+ if (sve_max_virtualisable_vl < sve_max_vl)
+ pr_warn("SVE: unvirtualisable vector lengths present\n");
+
sve_efi_setup();
}
generated by cgit v1.2.3 (git 2.39.0) at 2024-09-21 10:50:56 +0300