Re: [libvirt] [PATCH 11/26] cpu_x86: Allow multiple signatures for a CPU model

CPU signatures in the cpu_map serve as a hint for CPUID to CPU model matching algorithm. If the CPU signatures matches any CPU model in the cpu_map, this model will be the preferred one. This works out well and solved several mismatches, but in real world CPUs which should match a single CPU model may be produced with several different signatures. For example, low voltage Broadwell CPUs for laptops and Broadwell CPUs for servers differ in CPU model numbers while we should detect them all as Broadwell CPU model. This patch adds support for storing several signatures for a single CPU model to make this hint useful for more CPUs. Later commits will provide additional signatures for existing CPU models, which will correct some results in our CPU test suite. Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; --- src/cpu/cpu_x86.c | 104 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 86 insertions(+), 18 deletions(-) diff --git a/src/cpu/cpu_x86.c b/src/cpu/cpu_x86.c index c2f22f399f..89303400af 100644 --- a/src/cpu/cpu_x86.c +++ b/src/cpu/cpu_x86.c @@ -974,11 +975,29 @@ x86ModelFree(virCPUx86ModelPtr model) return; VIR_FREE(model->name); + VIR_FREE(model->signatures); virCPUx86DataClear(&model->data); VIR_FREE(model); } +static int +x86ModelCopySignatures(virCPUx86ModelPtr dst, + virCPUx86ModelPtr src) +{

+ size_t i; + + if (VIR_ALLOC_N(dst->signatures, src->nsignatures) < 0) + return -1; + + dst->nsignatures = src->nsignatures; + for (i = 0; i < src->nsignatures; i++) + dst->signatures[i] = src->signatures[i]; + + return 0; +} + + static virCPUx86ModelPtr x86ModelCopy(virCPUx86ModelPtr model) { @@ -986,13 +1005,13 @@ x86ModelCopy(virCPUx86ModelPtr model) if (VIR_ALLOC(copy) < 0 || VIR_STRDUP(copy->name, model->name) < 0 || + x86ModelCopySignatures(copy, model) < 0 || x86DataCopy(&copy->data, &model->data) < 0) { x86ModelFree(copy); return NULL; } copy->vendor = model->vendor; - copy->signature = model->signature; return copy; } @@ -1178,8 +1197,8 @@ x86ModelParseAncestor(virCPUx86ModelPtr model, } model->vendor = ancestor->vendor; - model->signature = ancestor->signature; - if (x86DataCopy(&model->data, &ancestor->data) < 0) + if (x86ModelCopySignatures(model, ancestor) < 0 || + x86DataCopy(&model->data, &ancestor->data) < 0) return -1; return 0; @@ -1187,16 +1206,32 @@ x86ModelParseAncestor(virCPUx86ModelPtr model, static int -x86ModelParseSignature(virCPUx86ModelPtr model, - xmlXPathContextPtr ctxt) +x86ModelParseSignatures(virCPUx86ModelPtr model, + xmlXPathContextPtr ctxt) { - int rc;

+ VIR_AUTOFREE(xmlNodePtr *) nodes = NULL; + xmlNodePtr root = ctxt->node; + size_t i; + int n; - if (virXPathBoolean("boolean(./signature)", ctxt)) { + if ((n = virXPathNodeSet("./signature", ctxt, &nodes)) <= 0) + return n; + + /* Remove inherited signatures. */ + VIR_FREE(model->signatures); + + model->nsignatures = n; + if (VIR_ALLOC_N(model->signatures, n) < 0) + return -1; + + for (i = 0; i < n; i++) { unsigned int sigFamily = 0; unsigned int sigModel = 0; + int rc; - rc = virXPathUInt("string(./signature/@family)", ctxt, &sigFamily); + ctxt->node = nodes[i]; + + rc = virXPathUInt("string(@family)", ctxt, &sigFamily);

if (rc < 0 || sigFamily == 0) { virReportError(VIR_ERR_INTERNAL_ERROR, _("Invalid CPU signature family in model %s"), @@ -1204,7 +1239,7 @@ x86ModelParseSignature(virCPUx86ModelPtr model, return -1; } - rc = virXPathUInt("string(./signature/@model)", ctxt, &sigModel); + rc = virXPathUInt("string(@model)", ctxt, &sigModel); if (rc < 0 || sigModel == 0) { virReportError(VIR_ERR_INTERNAL_ERROR, _("Invalid CPU signature model in model %s"), @@ -1212,9 +1247,10 @@ x86ModelParseSignature(virCPUx86ModelPtr model, return -1; } - model->signature = x86MakeSignature(sigFamily, sigModel, 0); + model->signatures[i] = x86MakeSignature(sigFamily, sigModel, 0); } + ctxt->node = root; return 0; } @@ -1311,7 +1347,7 @@ x86ModelParse(xmlXPathContextPtr ctxt, if (x86ModelParseAncestor(model, ctxt, map) < 0) goto cleanup; - if (x86ModelParseSignature(model, ctxt) < 0) + if (x86ModelParseSignatures(model, ctxt) < 0) goto cleanup; if (x86ModelParseVendor(model, ctxt, map) < 0) @@ -1615,7 +1651,8 @@ x86Compute(virCPUDefPtr host, &host_model->vendor->cpuid) < 0) goto error; - if (x86DataAddSignature(&guest_model->data, host_model->signature) < 0) + if (host_model->signatures && + x86DataAddSignature(&guest_model->data, *host_model->signatures) < 0) goto error; if (cpu->type == VIR_CPU_TYPE_GUEST @@ -1721,6 +1758,21 @@ virCPUx86Compare(virCPUDefPtr host, } +static bool +x86ModelHasSignature(virCPUx86ModelPtr model, + uint32_t signature) +{ + size_t i; + + for (i = 0; i < model->nsignatures; i++) { + if (model->signatures[i] == signature) + return true; + } + + return false; +} + + /* * Checks whether a candidate model is a better fit for the CPU data than the * current model. @@ -1762,8 +1814,8 @@ x86DecodeUseCandidate(virCPUx86ModelPtr current, * consider candidates with matching family/model. */ if (signature && - current->signature == signature && - candidate->signature != signature) { + x86ModelHasSignature(current, signature) && + !x86ModelHasSignature(candidate, signature)) { VIR_DEBUG("%s differs in signature from matching %s", cpuCandidate->model, cpuCurrent->model); return 0; @@ -1779,8 +1831,8 @@ x86DecodeUseCandidate(virCPUx86ModelPtr current, * result in longer list of features. */ if (signature && - candidate->signature == signature && - current->signature != signature) { + x86ModelHasSignature(candidate, signature) && + !x86ModelHasSignature(current, signature)) { VIR_DEBUG("%s provides matching signature", cpuCandidate->model); return 1; } @@ -1844,6 +1896,8 @@ x86Decode(virCPUDefPtr cpu, virCPUx86Data features = VIR_CPU_X86_DATA_INIT; virCPUx86VendorPtr vendor; virDomainCapsCPUModelPtr hvModel = NULL; + virBuffer sigBuf = VIR_BUFFER_INITIALIZER; + char *sigs = NULL; uint32_t signature; ssize_t i; int rc; @@ -1936,6 +1990,18 @@ x86Decode(virCPUDefPtr cpu, if (vendor && VIR_STRDUP(cpu->vendor, vendor->name) < 0) goto cleanup; + for (i = 0; i < model->nsignatures; i++) + virBufferAsprintf(&sigBuf, "%06x,", model->signatures[i]); + + virBufferTrim(&sigBuf, ",", -1); + if (virBufferCheckError(&sigBuf) < 0) + goto cleanup; + + sigs = virBufferContentAndReset(&sigBuf); +

+ VIR_DEBUG("Using CPU model %s (signatures %s) for CPU with signature %06lx", + model->name, sigs, (long)signature); + VIR_STEAL_PTR(cpu->model, cpuModel->model); VIR_STEAL_PTR(cpu->features, cpuModel->features); cpu->nfeatures = cpuModel->nfeatures;