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cpu_x86: Add support for stepping part of CPU signature

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CPU models defined in the cpu_map can use signature/@stepping attribute
to match a limited set of stepping numbers. The value is a bitmap for
bits 0..15 each corresponding to a single stepping value. For example,
stepping='4-6,9' will match 4, 5, 6, and 9. Omitting the attribute is
equivalent to stepping='0-15'.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
This commit is contained in:
Jiri Denemark 2020-03-26 20:34:56 +01:00
parent 70f3041d39
commit c7a2794995
1 changed files with 50 additions and 10 deletions
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60
src/cpu/cpu_x86.c
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@ -125,6 +125,7 @@ typedef struct _virCPUx86Signature virCPUx86Signature;
struct _virCPUx86Signature {
unsigned int family;
unsigned int model;
virBitmapPtr stepping;
};
typedef struct _virCPUx86Signatures virCPUx86Signatures;
@ -732,7 +733,17 @@ x86MakeSignature(unsigned int family,
static uint32_t
virCPUx86SignatureToCPUID(virCPUx86Signature *sig)
{
return x86MakeSignature(sig->family, sig->model, 0);
unsigned int stepping = 0;
if (sig->stepping) {
ssize_t firstBit;
firstBit = virBitmapNextSetBit(sig->stepping, -1);
if (firstBit >= 0)
stepping = firstBit;
}
return x86MakeSignature(sig->family, sig->model, stepping);
}
@ -767,8 +778,8 @@ x86DataToSignatureFull(const virCPUx86Data *data,
}
/* Mask out irrelevant bits (R and Step) from processor signature. */
#define SIGNATURE_MASK 0x0fff3ff0
/* Mask out reserved bits from processor signature. */
#define SIGNATURE_MASK 0x0fff3fff
static uint32_t
x86DataToSignature(const virCPUx86Data *data)
@ -1134,9 +1145,14 @@ virCPUx86SignaturesNew(size_t count)
static void
virCPUx86SignaturesFree(virCPUx86SignaturesPtr sigs)
{
size_t i;
if (!sigs)
return;
for (i = 0; i < sigs->count; i++)
virBitmapFree(sigs->items[i].stepping);
g_free(sigs->items);
g_free(sigs);
}
@ -1153,8 +1169,12 @@ virCPUx86SignaturesCopy(virCPUx86SignaturesPtr src)
dst = virCPUx86SignaturesNew(src->count);
for (i = 0; i < src->count; i++)
dst->items[i] = src->items[i];
for (i = 0; i < src->count; i++) {
dst->items[i].family = src->items[i].family;
dst->items[i].model = src->items[i].model;
if (src->items[i].stepping)
dst->items[i].stepping = virBitmapNewCopy(src->items[i].stepping);
}
return dst;
}
@ -1176,7 +1196,9 @@ virCPUx86SignaturesMatch(virCPUx86SignaturesPtr sigs,
for (i = 0; i < sigs->count; i++) {
if (sigs->items[i].family == family &&
sigs->items[i].model == model)
sigs->items[i].model == model &&
(!sigs->items[i].stepping ||
virBitmapIsBitSet(sigs->items[i].stepping, stepping)))
return true;
}
@ -1194,9 +1216,15 @@ virCPUx86SignaturesFormat(virCPUx86SignaturesPtr sigs)
return virBufferContentAndReset(&buf);
for (i = 0; i < sigs->count; i++) {
virBufferAsprintf(&buf, "(%u,%u,0), ",
g_autofree char *stepping = NULL;
if (sigs->items[i].stepping)
stepping = virBitmapFormat(sigs->items[i].stepping);
virBufferAsprintf(&buf, "(%u,%u,%s), ",
sigs->items[i].family,
sigs->items[i].model);
sigs->items[i].model,
stepping ? stepping : "0-15");
}
virBufferTrim(&buf, ", ");
@ -1473,6 +1501,7 @@ x86ModelParseSignatures(virCPUx86ModelPtr model,
for (i = 0; i < n; i++) {
virCPUx86Signature *sig = &model->signatures->items[i];
g_autofree char *stepping = NULL;
int rc;
ctxt->node = nodes[i];
@ -1492,6 +1521,11 @@ x86ModelParseSignatures(virCPUx86ModelPtr model,
model->name);
return -1;
}
stepping = virXPathString("string(@stepping)", ctxt);
/* stepping corresponds to 4 bits in 32b signature, see above */
if (stepping && virBitmapParse(stepping, &sig->stepping, 16) < 0)
return -1;
}
ctxt->node = root;
@ -2090,6 +2124,9 @@ x86Decode(virCPUDefPtr cpu,
virDomainCapsCPUModelPtr hvModel = NULL;
g_autofree char *sigs = NULL;
uint32_t signature;
unsigned int sigFamily;
unsigned int sigModel;
unsigned int sigStepping;
ssize_t i;
int rc;
@ -2103,6 +2140,7 @@ x86Decode(virCPUDefPtr cpu,
vendor = x86DataToVendor(&data, map);
signature = x86DataToSignature(&data);
virCPUx86SignatureFromCPUID(signature, &sigFamily, &sigModel, &sigStepping);
x86DataFilterTSX(&data, vendor, map);
@ -2184,8 +2222,10 @@ x86Decode(virCPUDefPtr cpu,
sigs = virCPUx86SignaturesFormat(model->signatures);
VIR_DEBUG("Using CPU model %s (signatures %s) for CPU with signature %06lx",
model->name, NULLSTR(sigs), (unsigned long)signature);
VIR_DEBUG("Using CPU model %s with signatures [%s] for "
"CPU with signature (%u,%u,%u)",
model->name, NULLSTR(sigs),
sigFamily, sigModel, sigStepping);
cpu->model = g_steal_pointer(&cpuModel->model);
cpu->features = g_steal_pointer(&cpuModel->features);