From 37656470f67398dd10101d7d940d660053f60ff5 Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Wed, 5 Oct 2022 00:56:43 +0200 Subject: [PATCH] KVM: x86: Implement MSR_CORE_THREAD_COUNT MSR The MSR_CORE_THREAD_COUNT MSR describes CPU package topology, such as number of threads and cores for a given package. This is information that QEMU has readily available and can provide through the new user space MSR deflection interface. This patch propagates the existing hvf logic from patch 027ac0cb516 ("target/i386/hvf: add rdmsr 35H MSR_CORE_THREAD_COUNT") to KVM. Signed-off-by: Alexander Graf Message-Id: <20221004225643.65036-4-agraf@csgraf.de> Signed-off-by: Paolo Bonzini --- target/i386/kvm/kvm.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 1d9a50b02b..bed6c00f2c 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -2401,6 +2401,17 @@ static int kvm_get_supported_msrs(KVMState *s) return ret; } +static bool kvm_rdmsr_core_thread_count(X86CPU *cpu, uint32_t msr, + uint64_t *val) +{ + CPUState *cs = CPU(cpu); + + *val = cs->nr_threads * cs->nr_cores; /* thread count, bits 15..0 */ + *val |= ((uint32_t)cs->nr_cores << 16); /* core count, bits 31..16 */ + + return true; +} + static Notifier smram_machine_done; static KVMMemoryListener smram_listener; static AddressSpace smram_address_space; @@ -2613,6 +2624,8 @@ int kvm_arch_init(MachineState *ms, KVMState *s) } } if (kvm_vm_check_extension(s, KVM_CAP_X86_USER_SPACE_MSR)) { + bool r; + ret = kvm_vm_enable_cap(s, KVM_CAP_X86_USER_SPACE_MSR, 0, KVM_MSR_EXIT_REASON_FILTER); if (ret) { @@ -2620,6 +2633,14 @@ int kvm_arch_init(MachineState *ms, KVMState *s) strerror(-ret)); exit(1); } + + r = kvm_filter_msr(s, MSR_CORE_THREAD_COUNT, + kvm_rdmsr_core_thread_count, NULL); + if (!r) { + error_report("Could not install MSR_CORE_THREAD_COUNT handler: %s", + strerror(-ret)); + exit(1); + } } return 0; -- 2.11.4.GIT