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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v7 03/10] microcode: introduce a global cache of ucode patch
to replace the current per-cpu cache 'uci->mc'.
With the assumption that all CPUs in the system have the same signature
(family, model, stepping and 'pf'), one microcode update matches with
one cpu should match with others. And Having multiple microcode revisions
on different cpus would cause system unstable and is what should be
avoided. Hence, caching only one microcode update is good enough for all
cases.
Introduce a global variable, microcode_cache, to store the newest
matching microcode update. Whenever we get a new valid microcode update,
its revision id is compared against that of the microcode update to
determine whether the "microcode_cache" needs to be replaced. And now
this global cache is loaded to cpu in apply_microcode().
All operations on the cache is expected to be done with the
'microcode_mutex' hold.
Note that I deliberately avoid touching 'uci->mc' as I am going to
remove it completely in the next patch.
Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
---
Changes in v7:
- reworked to cache only one microcode patch rather than a list of
microcode patches.
Changes in v6:
- constify local variables and function parameters if possible
- comment that the global cache is protected by 'microcode_mutex'.
and add assertions to catch violations in microcode_{save/find}_patch()
Changes in v5:
- reword the commit description
- find_patch() and save_patch() are abstracted into common functions
with some hooks for AMD and Intel
---
xen/arch/x86/microcode.c | 36 ++++++++++++++++
xen/arch/x86/microcode_amd.c | 91 +++++++++++++++++++++++++++++++++++++----
xen/arch/x86/microcode_intel.c | 77 +++++++++++++++++++++++++++-------
xen/include/asm-x86/microcode.h | 15 +++++++
4 files changed, 197 insertions(+), 22 deletions(-)
diff --git a/xen/arch/x86/microcode.c b/xen/arch/x86/microcode.c
index 4163f50..cff86a9 100644
--- a/xen/arch/x86/microcode.c
+++ b/xen/arch/x86/microcode.c
@@ -61,6 +61,9 @@ static struct ucode_mod_blob __initdata ucode_blob;
*/
static bool_t __initdata ucode_scan;
+/* Protected by microcode_mutex */
+static struct microcode_patch *microcode_cache;
+
void __init microcode_set_module(unsigned int idx)
{
ucode_mod_idx = idx;
@@ -262,6 +265,39 @@ int microcode_resume_cpu(unsigned int cpu)
return err;
}
+const struct microcode_patch *microcode_get_cache(void)
+{
+ ASSERT(spin_is_locked(µcode_mutex));
+
+ return microcode_cache;
+}
+
+/* Return true if cache gets updated. Otherwise, return false */
+bool microcode_update_cache(struct microcode_patch *patch)
+{
+
+ ASSERT(spin_is_locked(µcode_mutex));
+
+ if ( !microcode_ops->match_cpu(patch) )
+ return false;
+
+ if ( !microcode_cache )
+ microcode_cache = patch;
+ else if ( microcode_ops->compare_patch(patch, microcode_cache) ==
+ NEW_UCODE )
+ {
+ microcode_ops->free_patch(microcode_cache);
+ microcode_cache = patch;
+ }
+ else
+ {
+ microcode_ops->free_patch(patch);
+ return false;
+ }
+
+ return true;
+}
+
static int microcode_update_cpu(const void *buf, size_t size)
{
int err;
diff --git a/xen/arch/x86/microcode_amd.c b/xen/arch/x86/microcode_amd.c
index 7a854c0..1f05899 100644
--- a/xen/arch/x86/microcode_amd.c
+++ b/xen/arch/x86/microcode_amd.c
@@ -190,24 +190,85 @@ static bool_t microcode_fits(const struct microcode_amd
*mc_amd,
return 1;
}
+static bool match_cpu(const struct microcode_patch *patch)
+{
+ if ( !patch )
+ return false;
+ return microcode_fits(patch->mc_amd, smp_processor_id());
+}
+
+static struct microcode_patch *alloc_microcode_patch(
+ const struct microcode_amd *mc_amd)
+{
+ struct microcode_patch *microcode_patch = xmalloc(struct microcode_patch);
+ struct microcode_amd *cache = xmalloc(struct microcode_amd);
+ void *mpb = xmalloc_bytes(mc_amd->mpb_size);
+ struct equiv_cpu_entry *equiv_cpu_table =
+ xmalloc_bytes(mc_amd->equiv_cpu_table_size);
+
+ if ( !microcode_patch || !cache || !mpb || !equiv_cpu_table )
+ {
+ xfree(microcode_patch);
+ xfree(cache);
+ xfree(mpb);
+ xfree(equiv_cpu_table);
+ printk(XENLOG_ERR "microcode: Can not allocate memory\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ cache->equiv_cpu_table = equiv_cpu_table;
+ cache->mpb = mpb;
+ memcpy(cache->equiv_cpu_table, mc_amd->equiv_cpu_table,
+ mc_amd->equiv_cpu_table_size);
+ memcpy(cache->mpb, mc_amd->mpb, mc_amd->mpb_size);
+ cache->equiv_cpu_table_size = mc_amd->equiv_cpu_table_size;
+ cache->mpb_size = mc_amd->mpb_size;
+ microcode_patch->mc_amd = cache;
+
+ return microcode_patch;
+}
+
+static void free_patch(struct microcode_patch *microcode_patch)
+{
+ struct microcode_amd *mc_amd = microcode_patch->mc_amd;
+
+ xfree(mc_amd->equiv_cpu_table);
+ xfree(mc_amd->mpb);
+ xfree(mc_amd);
+ xfree(microcode_patch);
+}
+
+static enum microcode_match_result compare_patch(
+ const struct microcode_patch *new, const struct microcode_patch *old)
+{
+ const struct microcode_amd *new_mc = new->mc_amd;
+ const struct microcode_header_amd *new_header = new_mc->mpb;
+ const struct microcode_amd *old_mc = old->mc_amd;
+ const struct microcode_header_amd *old_header = old_mc->mpb;
+
+ if ( new_header->processor_rev_id == old_header->processor_rev_id )
+ return (new_header->patch_id > old_header->patch_id) ?
+ NEW_UCODE : OLD_UCODE;
+
+ return MIS_UCODE;
+}
+
static int apply_microcode(unsigned int cpu)
{
unsigned long flags;
struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
uint32_t rev;
- struct microcode_amd *mc_amd = uci->mc.mc_amd;
- struct microcode_header_amd *hdr;
int hw_err;
+ const struct microcode_header_amd *hdr;
+ const struct microcode_patch *patch = microcode_get_cache();
/* We should bind the task to the CPU */
BUG_ON(raw_smp_processor_id() != cpu);
- if ( mc_amd == NULL )
+ if ( !match_cpu(patch) )
return -EINVAL;
- hdr = mc_amd->mpb;
- if ( hdr == NULL )
- return -EINVAL;
+ hdr = patch->mc_amd->mpb;
spin_lock_irqsave(µcode_update_lock, flags);
@@ -497,7 +558,20 @@ static int cpu_request_microcode(unsigned int cpu, const
void *buf,
while ( (error = get_ucode_from_buffer_amd(mc_amd, buf, bufsize,
&offset)) == 0 )
{
- if ( microcode_fits(mc_amd, cpu) )
+ struct microcode_patch *new_patch = alloc_microcode_patch(mc_amd);
+
+ if ( IS_ERR(new_patch) )
+ {
+ error = PTR_ERR(new_patch);
+ break;
+ }
+
+ if ( match_cpu(new_patch) )
+ microcode_update_cache(new_patch);
+ else
+ free_patch(new_patch);
+
+ if ( match_cpu(microcode_get_cache()) )
{
error = apply_microcode(cpu);
if ( error )
@@ -639,6 +713,9 @@ static const struct microcode_ops microcode_amd_ops = {
.collect_cpu_info = collect_cpu_info,
.apply_microcode = apply_microcode,
.start_update = start_update,
+ .free_patch = free_patch,
+ .compare_patch = compare_patch,
+ .match_cpu = match_cpu,
};
int __init microcode_init_amd(void)
diff --git a/xen/arch/x86/microcode_intel.c b/xen/arch/x86/microcode_intel.c
index ecec83b..d3405a0 100644
--- a/xen/arch/x86/microcode_intel.c
+++ b/xen/arch/x86/microcode_intel.c
@@ -248,6 +248,32 @@ static int microcode_sanity_check(void *mc)
return 0;
}
+static bool match_cpu(const struct microcode_patch *patch)
+{
+ const struct ucode_cpu_info *uci = &this_cpu(ucode_cpu_info);
+
+ if ( !patch )
+ return false;
+
+ return microcode_update_match(&patch->mc_intel->hdr, uci->cpu_sig.sig,
+ uci->cpu_sig.pf, uci->cpu_sig.rev) ==
NEW_UCODE;
+}
+
+static void free_patch(struct microcode_patch *patch)
+{
+ xfree(patch->mc_intel);
+ xfree(patch);
+}
+
+static enum microcode_match_result compare_patch(
+ const struct microcode_patch *new, const struct microcode_patch *old)
+{
+ const struct microcode_header_intel *old_header = &old->mc_intel->hdr;
+
+ return microcode_update_match(&new->mc_intel->hdr, old_header->sig,
+ old_header->pf, old_header->rev);
+}
+
/*
* return 0 - no update found
* return 1 - found update
@@ -258,10 +284,26 @@ static int get_matching_microcode(const void *mc,
unsigned int cpu)
struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu);
const struct microcode_header_intel *mc_header = mc;
unsigned long total_size = get_totalsize(mc_header);
- void *new_mc;
+ void *new_mc = xmalloc_bytes(total_size);
+ struct microcode_patch *new_patch = xmalloc(struct microcode_patch);
+
+ if ( !new_patch || !new_mc )
+ {
+ xfree(new_patch);
+ xfree(new_mc);
+ printk(XENLOG_ERR "microcode: Can not allocate memory\n");
+ return -ENOMEM;
+ }
+ memcpy(new_mc, mc, total_size);
+ new_patch->mc_intel = new_mc;
- if ( microcode_update_match(mc, uci->cpu_sig.sig, uci->cpu_sig.pf,
- uci->cpu_sig.rev) != NEW_UCODE )
+ if ( !match_cpu(new_patch) )
+ {
+ free_patch(new_patch);
+ return 0;
+ }
+
+ if ( !microcode_update_cache(new_patch) )
return 0;
pr_debug("microcode: CPU%d found a matching microcode update with"
@@ -277,6 +319,7 @@ static int get_matching_microcode(const void *mc, unsigned
int cpu)
memcpy(new_mc, mc, total_size);
xfree(uci->mc.mc_intel);
uci->mc.mc_intel = new_mc;
+
return 1;
}
@@ -287,18 +330,22 @@ static int apply_microcode(unsigned int cpu)
unsigned int val[2];
unsigned int cpu_num = raw_smp_processor_id();
struct ucode_cpu_info *uci = &per_cpu(ucode_cpu_info, cpu_num);
+ const struct microcode_intel *mc_intel;
+ const struct microcode_patch *patch = microcode_get_cache();
/* We should bind the task to the CPU */
BUG_ON(cpu_num != cpu);
- if ( uci->mc.mc_intel == NULL )
+ if ( !match_cpu(patch) )
return -EINVAL;
+ mc_intel = patch->mc_intel;
+
/* serialize access to the physical write to MSR 0x79 */
spin_lock_irqsave(µcode_update_lock, flags);
/* write microcode via MSR 0x79 */
- wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)uci->mc.mc_intel->bits);
+ wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc_intel->bits);
wrmsrl(MSR_IA32_UCODE_REV, 0x0ULL);
/* As documented in the SDM: Do a CPUID 1 here */
@@ -309,19 +356,19 @@ static int apply_microcode(unsigned int cpu)
val[1] = (uint32_t)(msr_content >> 32);
spin_unlock_irqrestore(µcode_update_lock, flags);
- if ( val[1] != uci->mc.mc_intel->hdr.rev )
+ if ( val[1] != mc_intel->hdr.rev )
{
printk(KERN_ERR "microcode: CPU%d update from revision "
"%#x to %#x failed. Resulting revision is %#x.\n", cpu_num,
- uci->cpu_sig.rev, uci->mc.mc_intel->hdr.rev, val[1]);
+ uci->cpu_sig.rev, mc_intel->hdr.rev, val[1]);
return -EIO;
}
printk(KERN_INFO "microcode: CPU%d updated from revision "
"%#x to %#x, date = %04x-%02x-%02x \n",
cpu_num, uci->cpu_sig.rev, val[1],
- uci->mc.mc_intel->hdr.year,
- uci->mc.mc_intel->hdr.month,
- uci->mc.mc_intel->hdr.day);
+ mc_intel->hdr.year,
+ mc_intel->hdr.month,
+ mc_intel->hdr.day);
uci->cpu_sig.rev = val[1];
return 0;
@@ -361,7 +408,6 @@ static int cpu_request_microcode(unsigned int cpu, const
void *buf,
long offset = 0;
int error = 0;
void *mc;
- unsigned int matching_count = 0;
/* We should bind the task to the CPU */
BUG_ON(cpu != raw_smp_processor_id());
@@ -379,10 +425,8 @@ static int cpu_request_microcode(unsigned int cpu, const
void *buf,
* lets keep searching till the latest version
*/
if ( error == 1 )
- {
- matching_count++;
error = 0;
- }
+
xfree(mc);
}
if ( offset > 0 )
@@ -390,7 +434,7 @@ static int cpu_request_microcode(unsigned int cpu, const
void *buf,
if ( offset < 0 )
error = offset;
- if ( !error && matching_count )
+ if ( !error && match_cpu(microcode_get_cache()) )
error = apply_microcode(cpu);
return error;
@@ -406,6 +450,9 @@ static const struct microcode_ops microcode_intel_ops = {
.cpu_request_microcode = cpu_request_microcode,
.collect_cpu_info = collect_cpu_info,
.apply_microcode = apply_microcode,
+ .free_patch = free_patch,
+ .compare_patch = compare_patch,
+ .match_cpu = match_cpu,
};
int __init microcode_init_intel(void)
diff --git a/xen/include/asm-x86/microcode.h b/xen/include/asm-x86/microcode.h
index 73ebe9a..6541c58 100644
--- a/xen/include/asm-x86/microcode.h
+++ b/xen/include/asm-x86/microcode.h
@@ -12,6 +12,13 @@ enum microcode_match_result {
struct cpu_signature;
struct ucode_cpu_info;
+struct microcode_patch {
+ union {
+ struct microcode_intel *mc_intel;
+ struct microcode_amd *mc_amd;
+ };
+};
+
struct microcode_ops {
int (*microcode_resume_match)(unsigned int cpu, const void *mc);
int (*cpu_request_microcode)(unsigned int cpu, const void *buf,
@@ -19,6 +26,11 @@ struct microcode_ops {
int (*collect_cpu_info)(unsigned int cpu, struct cpu_signature *csig);
int (*apply_microcode)(unsigned int cpu);
int (*start_update)(void);
+ void (*free_patch)(struct microcode_patch *patch);
+ bool (*match_cpu)(const struct microcode_patch *patch);
+ enum microcode_match_result (*compare_patch)(
+ const struct microcode_patch *new,
+ const struct microcode_patch *old);
};
struct cpu_signature {
@@ -39,4 +51,7 @@ struct ucode_cpu_info {
DECLARE_PER_CPU(struct ucode_cpu_info, ucode_cpu_info);
extern const struct microcode_ops *microcode_ops;
+const struct microcode_patch *microcode_get_cache(void);
+bool microcode_update_cache(struct microcode_patch *patch);
+
#endif /* ASM_X86__MICROCODE_H */
--
1.8.3.1
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