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authorThadeu Lima de Souza Cascardo <cascardo@canonical.com>2020-01-31 18:56:55 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2020-02-05 17:28:07 +0300
commit64b38bd1906bb62a040b4e91815e56005db4784d (patch)
tree150605fae3625b5c78d460c7b3f30c224be2e7a2 /arch
parent7df003c85218b5f5b10a7f6418208f31e813f38f (diff)
downloadlinux-64b38bd1906bb62a040b4e91815e56005db4784d.tar.xz
x86/kvm: do not setup pv tlb flush when not paravirtualized
kvm_setup_pv_tlb_flush will waste memory and print a misguiding message when KVM paravirtualization is not available. Intel SDM says that the when cpuid is used with EAX higher than the maximum supported value for basic of extended function, the data for the highest supported basic function will be returned. So, in some systems, kvm_arch_para_features will return bogus data, causing kvm_setup_pv_tlb_flush to detect support for pv tlb flush. Testing for kvm_para_available will work as it checks for the hypervisor signature. Besides, when the "nopv" command line parameter is used, it should not continue as well, as kvm_guest_init will no be called in that case. Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/kvm.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 81045aabb6f4..d817f255aed8 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -736,6 +736,9 @@ static __init int kvm_setup_pv_tlb_flush(void)
{
int cpu;
+ if (!kvm_para_available() || nopv)
+ return 0;
+
if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
!kvm_para_has_hint(KVM_HINTS_REALTIME) &&
kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {