From ae102b5d7bccd29bc6015a3e0acefeaa90d097ac Mon Sep 17 00:00:00 2001 From: Jiri Denemark Date: Thu, 6 Apr 2017 13:52:30 +0200 Subject: [PATCH] qemu: Fix regression when hyperv/vendor_id feature is used qemuProcessVerifyHypervFeatures is supposed to check whether all requested hyperv features were actually honored by QEMU/KVM. This is done by checking the corresponding CPUID bits reported by the virtual CPU. In other words, it doesn't work for string properties, such as VIR_DOMAIN_HYPERV_VENDOR_ID (there is no CPUID bit we could check). We could theoretically check all 96 bits corresponding to the vendor string, but luckily we don't have to check the feature at all. If QEMU is too old to support hyperv features, the domain won't even start. Otherwise, it is always supported. Without this patch, libvirt refuses to start a domain which contains reporting internal error: "unknown CPU feature __kvm_hv_vendor_id. This regression was introduced by commit v3.1.0-186-ge9dbe7011, which (by fixing the virCPUDataCheckFeature condition in qemuProcessVerifyHypervFeatures) revealed an old bug in the feature verification code. It's been there ever since the verification was implemented by commit v1.3.3-rc1-5-g95bbe4bf5, which effectively did not check VIR_DOMAIN_HYPERV_VENDOR_ID at all. https://bugzilla.redhat.com/show_bug.cgi?id=1439424 Signed-off-by: Jiri Denemark --- src/qemu/qemu_process.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index e450d0647e..8323a18316 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -3793,6 +3793,10 @@ qemuProcessVerifyHypervFeatures(virDomainDefPtr def, int rc; for (i = 0; i < VIR_DOMAIN_HYPERV_LAST; i++) { + /* always supported string property */ + if (i == VIR_DOMAIN_HYPERV_VENDOR_ID) + continue; + if (def->hyperv_features[i] != VIR_TRISTATE_SWITCH_ON) continue; @@ -3821,13 +3825,13 @@ qemuProcessVerifyHypervFeatures(virDomainDefPtr def, case VIR_DOMAIN_HYPERV_SYNIC: case VIR_DOMAIN_HYPERV_STIMER: case VIR_DOMAIN_HYPERV_RESET: - case VIR_DOMAIN_HYPERV_VENDOR_ID: virReportError(VIR_ERR_CONFIG_UNSUPPORTED, _("host doesn't support hyperv '%s' feature"), virDomainHypervTypeToString(i)); return -1; /* coverity[dead_error_begin] */ + case VIR_DOMAIN_HYPERV_VENDOR_ID: case VIR_DOMAIN_HYPERV_LAST: break; }