Commit d71b62a1 authored by Eduardo Habkost's avatar Eduardo Habkost
Browse files

target-i386: kvm: Allocate kvm_msrs struct once per VCPU 



Instead of using 2400 bytes in the stack for 150 MSR entries in
kvm_get_msrs() and kvm_put_msrs(), allocate a buffer once for
each VCPU.

Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarEduardo Habkost <ehabkost@redhat.com>
parent 42ecabaa

target-i386/cpu.h

+4 −0
Original line number Diff line number Diff line
@@ -1124,6 +1124,8 @@ typedef struct CPUX86State { 
    TPRAccess tpr_access_type;

} CPUX86State;



struct kvm_msrs;



/**

 * X86CPU:

 * @env: #CPUX86State
@@ -1176,6 +1178,8 @@ struct X86CPU { 
    struct DeviceState *apic_state;

    struct MemoryRegion *cpu_as_root, *cpu_as_mem, *smram;

    Notifier machine_done;



    struct kvm_msrs *kvm_msr_buf;

};



static inline X86CPU *x86_env_get_cpu(CPUX86State *env)

target-i386/kvm.c

+19 −18
Original line number Diff line number Diff line
@@ -57,6 +57,9 @@ 
#define MSR_KVM_WALL_CLOCK  0x11

#define MSR_KVM_SYSTEM_TIME 0x12



#define MSR_BUF_SIZE \

    (sizeof(struct kvm_msrs) + 150 * sizeof(struct kvm_msr_entry))



#ifndef BUS_MCEERR_AR

#define BUS_MCEERR_AR 4

#endif
@@ -914,6 +917,7 @@ int kvm_arch_init_vcpu(CPUState *cs) 
    if (has_xsave) {

        env->kvm_xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));

    }

    cpu->kvm_msr_buf = g_malloc0(MSR_BUF_SIZE);



    if (env->features[FEAT_1_EDX] & CPUID_MTRR) {

        has_msr_mtrr = true;
@@ -1462,6 +1466,11 @@ static void kvm_msr_entry_set(struct kvm_msr_entry *entry, 
    entry->data = value;

}



static void kvm_msr_buf_reset(X86CPU *cpu)

{

    memset(cpu->kvm_msr_buf, 0, MSR_BUF_SIZE);

}



static int kvm_put_tscdeadline_msr(X86CPU *cpu)

{

    CPUX86State *env = &cpu->env;
@@ -1528,14 +1537,12 @@ static int kvm_put_msr_feature_control(X86CPU *cpu) 
static int kvm_put_msrs(X86CPU *cpu, int level)

{

    CPUX86State *env = &cpu->env;

    struct {

        struct kvm_msrs info;

        struct kvm_msr_entry entries[150];

    } msr_data;

    struct kvm_msr_entry *msrs = msr_data.entries;

    struct kvm_msr_entry *msrs = cpu->kvm_msr_buf->entries;

    int n = 0, i;

    int ret;



    kvm_msr_buf_reset(cpu);



    kvm_msr_entry_set(&msrs[n++], MSR_IA32_SYSENTER_CS, env->sysenter_cs);

    kvm_msr_entry_set(&msrs[n++], MSR_IA32_SYSENTER_ESP, env->sysenter_esp);

    kvm_msr_entry_set(&msrs[n++], MSR_IA32_SYSENTER_EIP, env->sysenter_eip);
@@ -1724,11 +1731,9 @@ static int kvm_put_msrs(X86CPU *cpu, int level) 
        }

    }



    msr_data.info = (struct kvm_msrs) {

        .nmsrs = n,

    };

    cpu->kvm_msr_buf->nmsrs = n;



    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, &msr_data);

    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_SET_MSRS, cpu->kvm_msr_buf);

    if (ret < 0) {

        return ret;

    }
@@ -1944,13 +1949,11 @@ static int kvm_get_sregs(X86CPU *cpu) 
static int kvm_get_msrs(X86CPU *cpu)

{

    CPUX86State *env = &cpu->env;

    struct {

        struct kvm_msrs info;

        struct kvm_msr_entry entries[150];

    } msr_data;

    struct kvm_msr_entry *msrs = msr_data.entries;

    struct kvm_msr_entry *msrs = cpu->kvm_msr_buf->entries;

    int ret, i, n;



    kvm_msr_buf_reset(cpu);



    n = 0;

    msrs[n++].index = MSR_IA32_SYSENTER_CS;

    msrs[n++].index = MSR_IA32_SYSENTER_ESP;
@@ -2092,11 +2095,9 @@ static int kvm_get_msrs(X86CPU *cpu) 
        }

    }



    msr_data.info = (struct kvm_msrs) {

        .nmsrs = n,

    };

    cpu->kvm_msr_buf->nmsrs = n;



    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, &msr_data);

    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_MSRS, cpu->kvm_msr_buf);

    if (ret < 0) {

        return ret;

    }