Commit d27aa7f1 authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini
Browse files

KVM: x86: Clarify PMU related features bit manipulation 



kvm_pmu_cpuid_update makes a lot of bit manuiplation operations, when in fact
there are already unions that can be used instead. Changing the bit
manipulation to the union for clarity. This patch does not change the
functionality.

Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent a32e8459

arch/x86/kvm/pmu.c

+14 −10
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/types.h>

#include <linux/kvm_host.h>

#include <linux/perf_event.h>

#include <asm/perf_event.h>

#include "x86.h"

#include "cpuid.h"

#include "lapic.h"
@@ -463,7 +464,8 @@ void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu) 
{

	struct kvm_pmu *pmu = &vcpu->arch.pmu;

	struct kvm_cpuid_entry2 *entry;

	unsigned bitmap_len;

	union cpuid10_eax eax;

	union cpuid10_edx edx;



	pmu->nr_arch_gp_counters = 0;

	pmu->nr_arch_fixed_counters = 0;
@@ -475,25 +477,27 @@ void kvm_pmu_cpuid_update(struct kvm_vcpu *vcpu) 
	entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);

	if (!entry)

		return;

	eax.full = entry->eax;

	edx.full = entry->edx;



	pmu->version = entry->eax & 0xff;

	pmu->version = eax.split.version_id;

	if (!pmu->version)

		return;



	pmu->nr_arch_gp_counters = min((int)(entry->eax >> 8) & 0xff,

	pmu->nr_arch_gp_counters = min_t(int, eax.split.num_counters,

					INTEL_PMC_MAX_GENERIC);

	pmu->counter_bitmask[KVM_PMC_GP] =

		((u64)1 << ((entry->eax >> 16) & 0xff)) - 1;

	bitmap_len = (entry->eax >> 24) & 0xff;

	pmu->available_event_types = ~entry->ebx & ((1ull << bitmap_len) - 1);

	pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << eax.split.bit_width) - 1;

	pmu->available_event_types = ~entry->ebx &

					((1ull << eax.split.mask_length) - 1);



	if (pmu->version == 1) {

		pmu->nr_arch_fixed_counters = 0;

	} else {

		pmu->nr_arch_fixed_counters = min((int)(entry->edx & 0x1f),

		pmu->nr_arch_fixed_counters =

			min_t(int, edx.split.num_counters_fixed,

				INTEL_PMC_MAX_FIXED);

		pmu->counter_bitmask[KVM_PMC_FIXED] =

			((u64)1 << ((entry->edx >> 5) & 0xff)) - 1;

			((u64)1 << edx.split.bit_width_fixed) - 1;

	}



	pmu->global_ctrl = ((1 << pmu->nr_arch_gp_counters) - 1) |

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