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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] x86/HVM: allocate emulation cache entries dynamically
commit 23d60dbb0493b2f9ec1d89be5341eec2ee9dab32
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Jan 24 10:15:29 2025 +0100
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Jan 24 10:15:29 2025 +0100
x86/HVM: allocate emulation cache entries dynamically
Both caches may need higher capacity, and the upper bound will need to
be determined dynamically based on CPUID policy (for AMX'es TILELOAD /
TILESTORE at least).
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
xen/arch/x86/hvm/emulate.c | 51 ++++++++++++++++++++++++++--------
xen/arch/x86/include/asm/hvm/emulate.h | 7 ++++-
xen/arch/x86/include/asm/hvm/vcpu.h | 13 +--------
3 files changed, 46 insertions(+), 25 deletions(-)
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index f3b5800d81..427ac811a7 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -26,6 +26,18 @@
#include <asm/iocap.h>
#include <asm/vm_event.h>
+/*
+ * We may read or write up to m512 or up to a tile row as a number of
+ * device-model transactions.
+ */
+struct hvm_mmio_cache {
+ unsigned long gla;
+ unsigned int size; /* Amount of buffer[] actually used. */
+ unsigned int space:31; /* Allocated size of buffer[]. */
+ unsigned int dir:1;
+ uint8_t buffer[] __aligned(sizeof(long));
+};
+
struct hvmemul_cache
{
/* The cache is disabled as long as num_ents > max_ents. */
@@ -935,7 +947,7 @@ static int hvmemul_phys_mmio_access(
}
/* Accesses must not overflow the cache's buffer. */
- if ( offset + size > sizeof(cache->buffer) )
+ if ( offset + size > cache->space )
{
ASSERT_UNREACHABLE();
return X86EMUL_UNHANDLEABLE;
@@ -1011,7 +1023,7 @@ static struct hvm_mmio_cache *hvmemul_find_mmio_cache(
for ( i = 0; i < hvio->mmio_cache_count; i ++ )
{
- cache = &hvio->mmio_cache[i];
+ cache = hvio->mmio_cache[i];
if ( gla == cache->gla &&
dir == cache->dir )
@@ -1027,10 +1039,11 @@ static struct hvm_mmio_cache *hvmemul_find_mmio_cache(
++hvio->mmio_cache_count;
- cache = &hvio->mmio_cache[i];
- memset(cache, 0, sizeof (*cache));
+ cache = hvio->mmio_cache[i];
+ memset(cache->buffer, 0, cache->space);
cache->gla = gla;
+ cache->size = 0;
cache->dir = dir;
return cache;
@@ -2980,16 +2993,21 @@ void hvm_dump_emulation_state(const char *loglvl, const
char *prefix,
int hvmemul_cache_init(struct vcpu *v)
{
/*
- * No insn can access more than 16 independent linear addresses (AVX512F
- * scatters/gathers being the worst). Each such linear range can span a
- * page boundary, i.e. may require two page walks. Account for each insn
- * byte individually, for simplicity.
+ * AVX512F scatter/gather insns can access up to 16 independent linear
+ * addresses, up to 8 bytes size. Each such linear range can span a page
+ * boundary, i.e. may require two page walks.
+ */
+ unsigned int nents = 16 * 2 * (CONFIG_PAGING_LEVELS + 1);
+ unsigned int i, max_bytes = 64;
+ struct hvmemul_cache *cache;
+
+ /*
+ * Account for each insn byte individually, both for simplicity and to
+ * leave some slack space.
*/
- const unsigned int nents = (CONFIG_PAGING_LEVELS + 1) *
- (MAX_INST_LEN + 16 * 2);
- struct hvmemul_cache *cache = xmalloc_flex_struct(struct hvmemul_cache,
- ents, nents);
+ nents += MAX_INST_LEN * (CONFIG_PAGING_LEVELS + 1);
+ cache = xvmalloc_flex_struct(struct hvmemul_cache, ents, nents);
if ( !cache )
return -ENOMEM;
@@ -2999,6 +3017,15 @@ int hvmemul_cache_init(struct vcpu *v)
v->arch.hvm.hvm_io.cache = cache;
+ for ( i = 0; i < ARRAY_SIZE(v->arch.hvm.hvm_io.mmio_cache); ++i )
+ {
+ v->arch.hvm.hvm_io.mmio_cache[i] =
+ xvmalloc_flex_struct(struct hvm_mmio_cache, buffer, max_bytes);
+ if ( !v->arch.hvm.hvm_io.mmio_cache[i] )
+ return -ENOMEM;
+ v->arch.hvm.hvm_io.mmio_cache[i]->space = max_bytes;
+ }
+
return 0;
}
diff --git a/xen/arch/x86/include/asm/hvm/emulate.h
b/xen/arch/x86/include/asm/hvm/emulate.h
index 29d679442e..760ce5e77c 100644
--- a/xen/arch/x86/include/asm/hvm/emulate.h
+++ b/xen/arch/x86/include/asm/hvm/emulate.h
@@ -15,6 +15,7 @@
#include <xen/err.h>
#include <xen/mm.h>
#include <xen/sched.h>
+#include <xen/xvmalloc.h>
#include <asm/hvm/hvm.h>
#include <asm/x86_emulate.h>
@@ -119,7 +120,11 @@ int hvmemul_do_pio_buffer(uint16_t port,
int __must_check hvmemul_cache_init(struct vcpu *v);
static inline void hvmemul_cache_destroy(struct vcpu *v)
{
- XFREE(v->arch.hvm.hvm_io.cache);
+ unsigned int i;
+
+ for ( i = 0; i < ARRAY_SIZE(v->arch.hvm.hvm_io.mmio_cache); ++i )
+ XFREE(v->arch.hvm.hvm_io.mmio_cache[i]);
+ XVFREE(v->arch.hvm.hvm_io.cache);
}
bool hvmemul_read_cache(const struct vcpu *v, paddr_t gpa,
void *buffer, unsigned int size);
diff --git a/xen/arch/x86/include/asm/hvm/vcpu.h
b/xen/arch/x86/include/asm/hvm/vcpu.h
index 6d5845780d..196fed6d5d 100644
--- a/xen/arch/x86/include/asm/hvm/vcpu.h
+++ b/xen/arch/x86/include/asm/hvm/vcpu.h
@@ -22,17 +22,6 @@ struct hvm_vcpu_asid {
uint32_t asid;
};
-/*
- * We may read or write up to m512 as a number of device-model
- * transactions.
- */
-struct hvm_mmio_cache {
- unsigned long gla;
- unsigned int size;
- uint8_t dir;
- uint8_t buffer[64] __aligned(sizeof(long));
-};
-
struct hvm_vcpu_io {
/*
* HVM emulation:
@@ -48,7 +37,7 @@ struct hvm_vcpu_io {
* We may need to handle up to 3 distinct memory accesses per
* instruction.
*/
- struct hvm_mmio_cache mmio_cache[3];
+ struct hvm_mmio_cache *mmio_cache[3];
unsigned int mmio_cache_count;
/* For retries we shouldn't re-fetch the instruction. */
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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