Commit 5e725d11 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 0c2822b1 2c10b614

Documentation/admin-guide/hw-vuln/cross-thread-rsb.rst

+1 −2
Original line number Diff line number Diff line
@@ -88,5 +88,4 @@ capability to override those interceptions, but since this is not common, the 
mitigation that covers this path is not enabled by default.



The mitigation for the KVM_CAP_X86_DISABLE_EXITS capability can be turned on

using the boolean module parameter mitigate_smt_rsb, e.g.:

        kvm.mitigate_smt_rsb=1
 
using the boolean module parameter mitigate_smt_rsb, e.g. ``kvm.mitigate_smt_rsb=1``.

arch/x86/events/core.c

+7 −5
Original line number Diff line number Diff line
@@ -2974,17 +2974,19 @@ unsigned long perf_misc_flags(struct pt_regs *regs) 


void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap)

{

	if (!x86_pmu_initialized()) {

	/* This API doesn't currently support enumerating hybrid PMUs. */

	if (WARN_ON_ONCE(cpu_feature_enabled(X86_FEATURE_HYBRID_CPU)) ||

	    !x86_pmu_initialized()) {

		memset(cap, 0, sizeof(*cap));

		return;

	}



	cap->version		= x86_pmu.version;

	/*

	 * KVM doesn't support the hybrid PMU yet.

	 * Return the common value in global x86_pmu,

	 * which available for all cores.

	 * Note, hybrid CPU models get tracked as having hybrid PMUs even when

	 * all E-cores are disabled via BIOS.  When E-cores are disabled, the

	 * base PMU holds the correct number of counters for P-cores.

	 */

	cap->version		= x86_pmu.version;

	cap->num_counters_gp	= x86_pmu.num_counters;

	cap->num_counters_fixed	= x86_pmu.num_counters_fixed;

	cap->bit_width_gp	= x86_pmu.cntval_bits;

arch/x86/kvm/pmu.h

+19 −7
Original line number Diff line number Diff line
@@ -165,14 +165,26 @@ static inline void kvm_init_pmu_capability(void) 
{

	bool is_intel = boot_cpu_data.x86_vendor == X86_VENDOR_INTEL;



	/*

	 * Hybrid PMUs don't play nice with virtualization without careful

	 * configuration by userspace, and KVM's APIs for reporting supported

	 * vPMU features do not account for hybrid PMUs.  Disable vPMU support

	 * for hybrid PMUs until KVM gains a way to let userspace opt-in.

	 */

	if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU))

		enable_pmu = false;



	if (enable_pmu) {

		perf_get_x86_pmu_capability(&kvm_pmu_cap);



		/*

		 * For Intel, only support guest architectural pmu

		 * on a host with architectural pmu.

		 */

	if ((is_intel && !kvm_pmu_cap.version) || !kvm_pmu_cap.num_counters_gp)

		if ((is_intel && !kvm_pmu_cap.version) ||

		    !kvm_pmu_cap.num_counters_gp)

			enable_pmu = false;

	}



	if (!enable_pmu) {

		memset(&kvm_pmu_cap, 0, sizeof(kvm_pmu_cap));

arch/x86/kvm/x86.c

+1 −2
Original line number Diff line number Diff line
@@ -5263,12 +5263,11 @@ static void kvm_vcpu_ioctl_x86_get_debugregs(struct kvm_vcpu *vcpu, 
{

	unsigned long val;



	memset(dbgregs, 0, sizeof(*dbgregs));

	memcpy(dbgregs->db, vcpu->arch.db, sizeof(vcpu->arch.db));

	kvm_get_dr(vcpu, 6, &val);

	dbgregs->dr6 = val;

	dbgregs->dr7 = vcpu->arch.dr7;

	dbgregs->flags = 0;

	memset(&dbgregs->reserved, 0, sizeof(dbgregs->reserved));

}



static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,