| Message ID | 04c81a02c19a47e799e06b9c9ccb97e9a77f5927.1621885749.git.sidcha@amazon.de |
|---|---|
| State | New |
| Headers | show |
| Series | Handle hypercall code overlay page in userspace | expand |
On 24.05.21 21:54, Siddharth Chandrasekaran wrote: > kvm_put_one_msr() zeros cpu->kvm_msr_buf and uses it to set one MSR to > KVM. It is pretty wasteful as cpu->kvm_msr_buf is 4096 bytes long; > instead use a local buffer to avoid memset. > > Also, expose this method from kvm_i386.h as hyperv.c needs to set MSRs > in a subsequent patch. > > Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de> Reviewed-by: Alexander Graf <graf@amazon.com> Alex Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index d972eb4705..d19a2913fd 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -2534,12 +2534,16 @@ static void kvm_msr_entry_add(X86CPU *cpu, uint32_t index, uint64_t value) msrs->nmsrs++; } -static int kvm_put_one_msr(X86CPU *cpu, int index, uint64_t value) +int kvm_put_one_msr(X86CPU *cpu, int index, uint64_t value) { - kvm_msr_buf_reset(cpu); - kvm_msr_entry_add(cpu, index, value); + uint8_t msr_buf[sizeof(struct kvm_msrs) + sizeof(struct kvm_msr_entry)] = { 0 }; + struct kvm_msrs *msr = (struct kvm_msrs *)msr_buf; + + msr->nmsrs = 1; + msr->entries[0].index = index; + msr->entries[0].data = value; - return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf); + return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, msr); } void kvm_put_apicbase(X86CPU *cpu, uint64_t value) diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h index dc72508389..0c4cd08071 100644 --- a/target/i386/kvm/kvm_i386.h +++ b/target/i386/kvm/kvm_i386.h @@ -40,6 +40,7 @@ void kvm_synchronize_all_tsc(void); void kvm_arch_reset_vcpu(X86CPU *cs); void kvm_arch_do_init_vcpu(X86CPU *cs); +int kvm_put_one_msr(X86CPU *cpu, int index, uint64_t value); void kvm_put_apicbase(X86CPU *cpu, uint64_t value); bool kvm_enable_x2apic(void);
kvm_put_one_msr() zeros cpu->kvm_msr_buf and uses it to set one MSR to KVM. It is pretty wasteful as cpu->kvm_msr_buf is 4096 bytes long; instead use a local buffer to avoid memset. Also, expose this method from kvm_i386.h as hyperv.c needs to set MSRs in a subsequent patch. Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de> --- target/i386/kvm/kvm.c | 12 ++++++++---- target/i386/kvm/kvm_i386.h | 1 + 2 files changed, 9 insertions(+), 4 deletions(-)