kvm__setup_cpuid: use KVM_GET_SUPPORTED_CPUID to simplify cpuid setup

Let kernel setup "struct kvm_cpuid2" for us!

https://kerneltrap.org/mailarchive/linux-kernel/2010/4/27/4563640
Avi Kivity:
'''
No.  KVM_GET_CPUID2 reads what was set by KVM_SET_CPUID, as modified by
the guest executing the cpuid instruction.  KVM_GET_SUPPORTED_CPUID
tells userspace which bits are supported by the host cpu and kvm.

The API for KVM_GET_SUPPORTED_CPUID returns all cpuid leaves supported
in one go, IIRC.
'''
Signed-off-by: Asias He <asias.hejun@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

diff --git a/tools/kvm/cpuid.c b/tools/kvm/cpuid.c
index 7fdfb83a84b2b46fb4a0771b17c514c8ac713674..9119855b36466ad4b96b726875278e780dd96661 100644 (file)
--- a/tools/kvm/cpuid.c
+++ b/tools/kvm/cpuid.c
@@ -1,254 +1,24 @@
 #include "kvm/kvm.h"
-
-#include "kvm/cpufeature.h"
 #include "kvm/util.h"
 
 #include <sys/ioctl.h>
 #include <stdlib.h>
 #include <assert.h>
 
-static struct kvm_cpuid2 *kvm_cpuid__new(unsigned long nent)
-{
-       struct kvm_cpuid2 *self;
-
-       self = calloc(1, sizeof(*self) + (sizeof(struct kvm_cpuid_entry2) * nent));
-       if (!self)
-               die("out of memory");
-
-       return self;
-}
-
-static void kvm_cpuid__delete(struct kvm_cpuid2 *self)
-{
-       free(self);
-}
-
 #define        MAX_KVM_CPUID_ENTRIES           100
 
-enum {
-       CPUID_GET_VENDOR_ID             = 0x00,
-       CPUID_GET_HIGHEST_EXT_FUNCTION  = 0x80000000,
-};
-
-static uint32_t cpuid_highest_ext_func(void)
-{
-       struct cpuid_regs regs;
-
-       regs    = (struct cpuid_regs) {
-               .eax            = CPUID_GET_HIGHEST_EXT_FUNCTION,
-       };
-       host_cpuid(&regs);
-
-       return regs.eax;
-}
-
-static uint32_t cpuid_highest_func(void)
-{
-       struct cpuid_regs regs;
-
-       regs    = (struct cpuid_regs) {
-               .eax            = CPUID_GET_VENDOR_ID,
-       };
-       host_cpuid(&regs);
-
-       return regs.eax;
-}
-
 void kvm__setup_cpuid(struct kvm *self)
 {
        struct kvm_cpuid2 *kvm_cpuid;
-       uint32_t highest_ext;
-       uint32_t function;
-       uint32_t highest;
-       uint32_t ndx = 0;
-
-       kvm_cpuid       = kvm_cpuid__new(MAX_KVM_CPUID_ENTRIES);
-       highest         = cpuid_highest_func();
-
-       for (function = 0; function <= highest; function++) {
-               /*
-                * NOTE NOTE NOTE! Functions 0x0b and 0x0d seem to need special
-                * treatment as per qemu sources but we treat them as regular
-                * CPUID functions here because they are fairly exotic and the
-                * Linux kernel is not interested in them during boot up.
-                */
-               switch (function) {
-               case 0x00: {    /* Vendor-ID and Largest Standard Function */
-                       kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                               .function       = 0,
-                               .index          = 0,
-                               .flags          = 0,
-                               .eax            = 4,
-                               .ebx            = CPUID_VENDOR_INTEL_1,
-                               .ecx            = CPUID_VENDOR_INTEL_3,
-                               .edx            = CPUID_VENDOR_INTEL_2,
-                       };
-                       break;
-               }
-               case 0x01: {    /* Feature Information */
-                       struct cpuid_regs regs;
-
-                       regs    = (struct cpuid_regs) {
-                               .eax            = function,
-                       };
-                       host_cpuid(&regs);
-
-                       kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                               .function       = function,
-                               .index          = 0,
-                               .flags          = 0,
-                               .eax            = regs.eax,
-                               .ebx            = regs.ebx,
-                               .ecx            =
-                                       cpu_feature_disable(regs.ecx, KVM__X86_FEATURE_XSAVE) &
-                                       cpu_feature_disable(regs.ecx, KVM__X86_FEATURE_VMX),
-                               .edx            = regs.edx,
-                       };
-                       break;
-               }
-               case 0x02: {    /* Processor configuration descriptor */
-                       struct cpuid_regs regs;
-                       uint32_t times;
-
-                       regs    = (struct cpuid_regs) {
-                               .eax            = function,
-                       };
-                       host_cpuid(&regs);
-
-                       kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                               .function       = function,
-                               .index          = 0,
-                               .flags          = KVM_CPUID_FLAG_STATEFUL_FUNC | KVM_CPUID_FLAG_STATE_READ_NEXT,
-                               .eax            = regs.eax,
-                               .ebx            = regs.ebx,
-                               .ecx            = regs.ecx,
-                               .edx            = regs.edx,
-                       };
-
-                       times   = regs.eax & 0xff;      /* AL */
-
-                       while (times-- > 0) {
-                               regs    = (struct cpuid_regs) {
-                                       .eax            = function,
-                               };
-                               host_cpuid(&regs);
-
-                               kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                                       .function       = function,
-                                       .index          = 0,
-                                       .flags          = KVM_CPUID_FLAG_STATEFUL_FUNC,
-                                       .eax            = regs.eax,
-                                       .ebx            = regs.ebx,
-                                       .ecx            = regs.ecx,
-                                       .edx            = regs.edx,
-                               };
-                       }
-                       break;
-               }
-               case 0x04: { /* Deterministic Cache Parameters */
-                       uint32_t eax;
-                       /*
-                        * eax for n cores
-                        *     eax = (n - 1) << 26
-                        * eax for k threads
-                        *     eax = (k - 1) << 14
-                        * they could be OR'ified
-                        */
-                       eax = 0;
-
-                       /* L1 dcache info */
-                       kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                               .function       = function,
-                               .index          = 0,
-                               .flags          = KVM_CPUID_FLAG_SIGNIFCANT_INDEX | KVM_CPUID_FLAG_STATE_READ_NEXT,
-                               .eax            = eax | 0x0000121,
-                               .ebx            = 0x1c0003f,
-                               .ecx            = 0x000003f,
-                               .edx            = 0x0000001,
-                       };
-
-                       /* L1 icache info */
-                       kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                               .function       = function,
-                               .index          = 1,
-                               .flags          = KVM_CPUID_FLAG_SIGNIFCANT_INDEX | KVM_CPUID_FLAG_STATE_READ_NEXT,
-                               .eax            = eax | 0x0000122,
-                               .ebx            = 0x1c0003f,
-                               .ecx            = 0x000003f,
-                               .edx            = 0x0000001,
-                       };
-
-                       /* L2 cache info */
-                       kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                               .function       = function,
-                               .index          = 2,
-                               .flags          = KVM_CPUID_FLAG_SIGNIFCANT_INDEX | KVM_CPUID_FLAG_STATE_READ_NEXT,
-                               .eax            = eax | 0x0000143,
-                               .ebx            = 0x3c0003f,
-                               .ecx            = 0x0000fff,
-                               .edx            = 0x0000001,
-                       };
-
-                       /* End of list */
-                       kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                               .function       = function,
-                               .index          = 3,
-                               .flags          = 0,
-                               .eax            = 0,
-                               .ebx            = 0,
-                               .ecx            = 0,
-                               .edx            = 0,
-                       };
-                       break;
-               }
-               default: {
-                       struct cpuid_regs regs;
-
-                       regs    = (struct cpuid_regs) {
-                               .eax            = function,
-                       };
-                       host_cpuid(&regs);
-
-                       kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                               .function       = function,
-                               .index          = 0,
-                               .flags          = 0,
-                               .eax            = regs.eax,
-                               .ebx            = regs.ebx,
-                               .ecx            = regs.ecx,
-                               .edx            = regs.edx,
-                       };
-                       break;
-               }};
-       }
-
-       highest_ext     = cpuid_highest_ext_func();
-
-       for (function = CPUID_GET_HIGHEST_EXT_FUNCTION; function <= highest_ext; function++) {
-               struct cpuid_regs regs;
-
-               regs    = (struct cpuid_regs) {
-                       .eax            = function,
-               };
-               host_cpuid(&regs);
-
-               kvm_cpuid->entries[ndx++]       = (struct kvm_cpuid_entry2) {
-                       .function       = function,
-                       .index          = 0,
-                       .flags          = 0,
-                       .eax            = regs.eax,
-                       .ebx            = regs.ebx,
-                       .ecx            = regs.ecx,
-                       .edx            = regs.edx,
-               };
-       }
 
-       assert(ndx < MAX_KVM_CPUID_ENTRIES);
+       kvm_cpuid = calloc(1, sizeof(*kvm_cpuid) + MAX_KVM_CPUID_ENTRIES * sizeof(*kvm_cpuid->entries));
 
-       kvm_cpuid->nent         = ndx;
+       kvm_cpuid->nent = MAX_KVM_CPUID_ENTRIES;
+       if (ioctl(self->sys_fd, KVM_GET_SUPPORTED_CPUID, kvm_cpuid) < 0)
+               die_perror("KVM_GET_SUPPORTED_CPUID failed");
 
        if (ioctl(self->vcpu_fd, KVM_SET_CPUID2, kvm_cpuid) < 0)
                die_perror("KVM_SET_CPUID2 failed");
 
-       kvm_cpuid__delete(kvm_cpuid);
+       free(kvm_cpuid);
 }