Re: [libvirt] [PATCH] qemu: Refresh caps cache after booting a different kernel

Whenever a different kernel is booted, some capabilities related to KVM (such as CPUID bits) may change. We need to refresh the cache to see the changes. Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; --- Notes: The capabilities may also change if a parameter passed to a kvm module changes (kvm_intel.nested is a good example) so this is not a complete solution, but we're hopefully getting closer to it :-)

src/qemu/qemu_capabilities.c | 57 +++++++++++++++++++++++++++++++++++++------- src/qemu/qemu_capspriv.h | 1 + tests/qemucapsprobe.c | 2 +- 3 files changed, 50 insertions(+), 10 deletions(-) diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index ab0ea8ec0d..2c573827f1 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -52,6 +52,7 @@ #include <unistd.h> #include <sys/wait.h> #include <stdarg.h> +#include <sys/utsname.h> #define VIR_FROM_THIS VIR_FROM_QEMU @@ -510,6 +511,7 @@ struct _virQEMUCaps { unsigned int libvirtVersion; unsigned int microcodeVersion; char *package; + char *kernelVersion; virArch arch; @@ -2303,6 +2305,9 @@ virQEMUCapsPtr virQEMUCapsNewCopy(virQEMUCapsPtr qemuCaps) if (VIR_STRDUP(ret->package, qemuCaps->package) < 0) goto error; + if (VIR_STRDUP(ret->kernelVersion, qemuCaps->kernelVersion) < 0) + goto error; + ret->arch = qemuCaps->arch; if (qemuCaps->kvmCPUModels) { @@ -2363,6 +2368,7 @@ void virQEMUCapsDispose(void *obj) virBitmapFree(qemuCaps->flags); VIR_FREE(qemuCaps->package); + VIR_FREE(qemuCaps->kernelVersion); VIR_FREE(qemuCaps->binary); VIR_FREE(qemuCaps->gicCapabilities); @@ -3834,6 +3840,7 @@ struct _virQEMUCapsCachePriv { gid_t runGid; virArch hostArch; unsigned int microcodeVersion; + char *kernelVersion; }; typedef struct _virQEMUCapsCachePriv virQEMUCapsCachePriv; typedef virQEMUCapsCachePriv *virQEMUCapsCachePrivPtr; @@ -3845,6 +3852,7 @@ virQEMUCapsCachePrivFree(void *privData) virQEMUCapsCachePrivPtr priv = privData; VIR_FREE(priv->libDir); + VIR_FREE(priv->kernelVersion); VIR_FREE(priv); } @@ -3970,6 +3978,12 @@ virQEMUCapsLoadCache(virArch hostArch, goto cleanup; } + if (virXPathBoolean("boolean(./kernelVersion)", ctxt) > 0) { + qemuCaps->kernelVersion = virXPathString("string(./kernelVersion)", ctxt); + if (!qemuCaps->kernelVersion) + goto cleanup; + } + if (!(str = virXPathString("string(./arch)", ctxt))) { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("missing arch in QEMU capabilities cache")); @@ -4248,6 +4262,10 @@ virQEMUCapsFormatCache(virQEMUCapsPtr qemuCaps) virBufferAsprintf(&buf, "<package>%s</package>\n", qemuCaps->package); + if (qemuCaps->kernelVersion) + virBufferAsprintf(&buf, "<kernelVersion>%s</kernelVersion>\n", + qemuCaps->kernelVersion); + virBufferAsprintf(&buf, "<arch>%s</arch>\n", virArchToString(qemuCaps->arch)); @@ -4385,14 +4403,24 @@ virQEMUCapsIsValid(void *data, return false; } - if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_KVM) && - priv->microcodeVersion != qemuCaps->microcodeVersion) { - VIR_DEBUG("Outdated capabilities for '%s': microcode version changed " - "(%u vs %u)", - qemuCaps->binary, - priv->microcodeVersion, - qemuCaps->microcodeVersion); - return false; + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_KVM)) { + if (priv->microcodeVersion != qemuCaps->microcodeVersion) { + VIR_DEBUG("Outdated capabilities for '%s': microcode version " + "changed (%u vs %u)", + qemuCaps->binary, + priv->microcodeVersion, + qemuCaps->microcodeVersion); + return false; + } + + if (STRNEQ_NULLABLE(priv->kernelVersion, qemuCaps->kernelVersion)) { + VIR_DEBUG("Outdated capabilities for '%s': kernel version changed " + "('%s' vs '%s')", + qemuCaps->binary, + priv->kernelVersion, + qemuCaps->kernelVersion); + return false; + } } return true; @@ -5228,6 +5256,7 @@ virQEMUCapsNewForBinaryInternal(virArch hostArch, uid_t runUid, gid_t runGid, unsigned int microcodeVersion, + const char *kernelVersion, bool qmpOnly) { virQEMUCapsPtr qemuCaps; @@ -5284,9 +5313,13 @@ virQEMUCapsNewForBinaryInternal(virArch hostArch, virQEMUCapsInitHostCPUModel(qemuCaps, hostArch, VIR_DOMAIN_VIRT_KVM); virQEMUCapsInitHostCPUModel(qemuCaps, hostArch, VIR_DOMAIN_VIRT_QEMU); - if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_KVM)) + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_KVM)) { qemuCaps->microcodeVersion = microcodeVersion; + if (VIR_STRDUP(qemuCaps->kernelVersion, kernelVersion) < 0) + goto error; + } + cleanup: VIR_FREE(qmperr); return qemuCaps; @@ -5309,6 +5342,7 @@ virQEMUCapsNewData(const char *binary, priv->runUid, priv->runGid, priv->microcodeVersion, + priv->kernelVersion, false); } @@ -5397,6 +5431,7 @@ virQEMUCapsCacheNew(const char *libDir, char *capsCacheDir = NULL; virFileCachePtr cache = NULL; virQEMUCapsCachePrivPtr priv = NULL; + struct utsname uts = { 0 }; if (virAsprintf(&capsCacheDir, "%s/capabilities", cacheDir) < 0) goto error; @@ -5417,6 +5452,10 @@ virQEMUCapsCacheNew(const char *libDir, priv->runGid = runGid; priv->microcodeVersion = microcodeVersion; + if (uname(&uts) == 0 && + virAsprintf(&priv->kernelVersion, "%s %s", uts.release, uts.version) < 0) + goto error; + cleanup: VIR_FREE(capsCacheDir); return cache; diff --git a/src/qemu/qemu_capspriv.h b/src/qemu/qemu_capspriv.h index 98d163b920..222f3368e3 100644 --- a/src/qemu/qemu_capspriv.h +++ b/src/qemu/qemu_capspriv.h @@ -37,6 +37,7 @@ virQEMUCapsNewForBinaryInternal(virArch hostArch, uid_t runUid, gid_t runGid, unsigned int microcodeVersion, + const char *kernelVersion, bool qmpOnly); int virQEMUCapsLoadCache(virArch hostArch, diff --git a/tests/qemucapsprobe.c b/tests/qemucapsprobe.c index a5f5a38b16..7d60246949 100644 --- a/tests/qemucapsprobe.c +++ b/tests/qemucapsprobe.c @@ -72,7 +72,7 @@ main(int argc, char **argv) return EXIT_FAILURE; if (!(caps = virQEMUCapsNewForBinaryInternal(VIR_ARCH_NONE, argv[1], "/tmp", - -1, -1, 0, true))) + -1, -1, 0, NULL, true))) return EXIT_FAILURE; virObjectUnref(caps);