From 5938aa17b49595150cade3ddc2c1929ecd0df39a Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 23 Feb 2018 10:17:56 +0100 Subject: [PATCH] x86/PV: correctly count MSRs to migrate Signed-off-by: Jan Beulich --- xen/arch/x86/domctl.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c index 0c9fe39a18..659dc9f4a2 100644 --- a/xen/arch/x86/domctl.c +++ b/xen/arch/x86/domctl.c @@ -1260,7 +1260,8 @@ long arch_do_domctl( struct xen_domctl_vcpu_msrs *vmsrs = &domctl->u.vcpu_msrs; struct xen_domctl_vcpu_msr msr; struct vcpu *v; - uint32_t nr_msrs = 0; + uint32_t nr_msrs = 0, edx, dummy; + bool has_ibrsb; ret = -ESRCH; if ( (vmsrs->vcpu >= d->max_vcpus) || @@ -1276,6 +1277,10 @@ long arch_do_domctl( if ( boot_cpu_has(X86_FEATURE_DBEXT) ) nr_msrs += 4; + domain_cpuid(d, 7, 0, &dummy, &dummy, &dummy, &edx); + has_ibrsb = (edx & cpufeat_mask(X86_FEATURE_IBRSB)); + nr_msrs += !!cpu_has_cpuid_faulting + has_ibrsb; + if ( domctl->cmd == XEN_DOMCTL_get_vcpu_msrs ) { ret = 0; copyback = 1; @@ -1285,8 +1290,6 @@ long arch_do_domctl( vmsrs->msr_count = nr_msrs; else { - uint32_t edx, dummy; - i = 0; vcpu_pause(v); @@ -1337,9 +1340,7 @@ long arch_do_domctl( ++i; } - domain_cpuid(d, 7, 0, &dummy, &dummy, &dummy, &edx); - if ( (edx & cpufeat_mask(X86_FEATURE_IBRSB)) && - v->arch.spec_ctrl ) + if ( has_ibrsb && v->arch.spec_ctrl ) { if ( i < vmsrs->msr_count && !ret ) {