Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm/x86 fixes from Paolo Bonzini:
- zero all padding for KVM_GET_DEBUGREGS
- fix rST warning
- disable vPMU support on hybrid CPUs
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
kvm: initialize all of the kvm_debugregs structure before sending it to userspace
perf/x86: Refuse to export capabilities for hybrid PMUs
KVM: x86/pmu: Disable vPMU support on hybrid CPUs (host PMUs)
Documentation/hw-vuln: Fix rST warning
+28
-16
+1
-2
Documentation/admin-guide/hw-vuln/cross-thread-rsb.rst
+1
-2
Documentation/admin-guide/hw-vuln/cross-thread-rsb.rst
···
88
88
mitigation that covers this path is not enabled by default.
89
89
90
90
The mitigation for the KVM_CAP_X86_DISABLE_EXITS capability can be turned on
91
-
using the boolean module parameter mitigate_smt_rsb, e.g.:
92
-
kvm.mitigate_smt_rsb=1
91
+
using the boolean module parameter mitigate_smt_rsb, e.g. ``kvm.mitigate_smt_rsb=1``.
+7
-5
arch/x86/events/core.c
+7
-5
arch/x86/events/core.c
···
2974
2974
2975
2975
void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap)
2976
2976
{
2977
-
if (!x86_pmu_initialized()) {
2977
+
/* This API doesn't currently support enumerating hybrid PMUs. */
2978
+
if (WARN_ON_ONCE(cpu_feature_enabled(X86_FEATURE_HYBRID_CPU)) ||
2979
+
!x86_pmu_initialized()) {
2978
2980
memset(cap, 0, sizeof(*cap));
2979
2981
return;
2980
2982
}
2981
2983
2982
-
cap->version = x86_pmu.version;
2983
2984
/*
2984
-
* KVM doesn't support the hybrid PMU yet.
2985
-
* Return the common value in global x86_pmu,
2986
-
* which available for all cores.
2985
+
* Note, hybrid CPU models get tracked as having hybrid PMUs even when
2986
+
* all E-cores are disabled via BIOS. When E-cores are disabled, the
2987
+
* base PMU holds the correct number of counters for P-cores.
2987
2988
*/
2989
+
cap->version = x86_pmu.version;
2988
2990
cap->num_counters_gp = x86_pmu.num_counters;
2989
2991
cap->num_counters_fixed = x86_pmu.num_counters_fixed;
2990
2992
cap->bit_width_gp = x86_pmu.cntval_bits;
+19
-7
arch/x86/kvm/pmu.h
+19
-7
arch/x86/kvm/pmu.h
···
165
165
{
166
166
bool is_intel = boot_cpu_data.x86_vendor == X86_VENDOR_INTEL;
167
167
168
-
perf_get_x86_pmu_capability(&kvm_pmu_cap);
169
-
170
-
/*
171
-
* For Intel, only support guest architectural pmu
172
-
* on a host with architectural pmu.
173
-
*/
174
-
if ((is_intel && !kvm_pmu_cap.version) || !kvm_pmu_cap.num_counters_gp)
168
+
/*
169
+
* Hybrid PMUs don't play nice with virtualization without careful
170
+
* configuration by userspace, and KVM's APIs for reporting supported
171
+
* vPMU features do not account for hybrid PMUs. Disable vPMU support
172
+
* for hybrid PMUs until KVM gains a way to let userspace opt-in.
173
+
*/
174
+
if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU))
175
175
enable_pmu = false;
176
+
177
+
if (enable_pmu) {
178
+
perf_get_x86_pmu_capability(&kvm_pmu_cap);
179
+
180
+
/*
181
+
* For Intel, only support guest architectural pmu
182
+
* on a host with architectural pmu.
183
+
*/
184
+
if ((is_intel && !kvm_pmu_cap.version) ||
185
+
!kvm_pmu_cap.num_counters_gp)
186
+
enable_pmu = false;
187
+
}
176
188
177
189
if (!enable_pmu) {
178
190
memset(&kvm_pmu_cap, 0, sizeof(kvm_pmu_cap));
+1
-2
arch/x86/kvm/x86.c
+1
-2
arch/x86/kvm/x86.c
···
5263
5263
{
5264
5264
unsigned long val;
5265
5265
5266
+
memset(dbgregs, 0, sizeof(*dbgregs));
5266
5267
memcpy(dbgregs->db, vcpu->arch.db, sizeof(vcpu->arch.db));
5267
5268
kvm_get_dr(vcpu, 6, &val);
5268
5269
dbgregs->dr6 = val;
5269
5270
dbgregs->dr7 = vcpu->arch.dr7;
5270
-
dbgregs->flags = 0;
5271
-
memset(&dbgregs->reserved, 0, sizeof(dbgregs->reserved));
5272
5271
}
5273
5272
5274
5273
static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,