[Qemu-devel] KVM: completely support cpuid functions 2, 4, b, d

[Qemu-devel] KVM: completely support cpuid functions 2, 4, b, d

[Amit Shah]

These patches add support for cpuid functions 2, 4, 0xb, 0xd. cpuid function
2 keeps returning values till we get a 0. The others take a 'count' parameter
in addition to the function number.

With these patches, KVM can run a VM started with a newer CPU type (coreduo,
core2duo). These patches also pave way for a "host" CPU type, where we could
pass the CPU type of the current host to the VM.

Please apply.

[Qemu-devel] [PATCH] KVM: CPUID takes ecx as input value for some functions

[Amit Shah]

The CPUID instruction takes the value of ECX as an input parameter
in addition to the value of EAX as the count for functions 4, 0xb
and 0xd. Make sure we pass the value to the instruction.

Also convert to the qemu-style whitespace for the surrounding code.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 qemu/target-i386/cpu.h       |    2 +-
 qemu/target-i386/helper.c    |   34 +++++++++++++++++-----------------
 qemu/target-i386/kvm.c       |    8 ++++----
 qemu/target-i386/op_helper.c |    2 +-
 4 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/qemu/target-i386/cpu.h b/qemu/target-i386/cpu.h
index 0a4f1d7..a6bbeb2 100644
--- a/qemu/target-i386/cpu.h
+++ b/qemu/target-i386/cpu.h
@@ -772,7 +772,7 @@ int cpu_x86_signal_handler(int host_signum, void *pinfo,
 int cpu_x86_handle_mmu_fault(CPUX86State *env, target_ulong addr,
                              int is_write, int mmu_idx, int is_softmmu);
 void cpu_x86_set_a20(CPUX86State *env, int a20_state);
-void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
+void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                    uint32_t *eax, uint32_t *ebx,
                    uint32_t *ecx, uint32_t *edx);
 
diff --git a/qemu/target-i386/helper.c b/qemu/target-i386/helper.c
index db9f397..de5891d 100644
--- a/qemu/target-i386/helper.c
+++ b/qemu/target-i386/helper.c
@@ -1375,7 +1375,8 @@ static void breakpoint_handler(CPUState *env)
 }
 #endif /* !CONFIG_USER_ONLY */
 
-static void host_cpuid(uint32_t function, uint32_t *eax, uint32_t *ebx,
+static void host_cpuid(uint32_t function, uint32_t count,
+                       uint32_t *eax, uint32_t *ebx,
                        uint32_t *ecx, uint32_t *edx)
 {
 #if defined(CONFIG_KVM)
@@ -1383,19 +1384,19 @@ static void host_cpuid(uint32_t function, uint32_t *eax, uint32_t *ebx,
 
 #ifdef __x86_64__
     asm volatile("cpuid"
-		 : "=a"(vec[0]), "=b"(vec[1]),
-		   "=c"(vec[2]), "=d"(vec[3])
-		 : "0"(function) : "cc");
+                 : "=a"(vec[0]), "=b"(vec[1]),
+                   "=c"(vec[2]), "=d"(vec[3])
+                 : "0"(function), "c"(count) : "cc");
 #else
     asm volatile("pusha \n\t"
-		 "cpuid \n\t"
-		 "mov %%eax, 0(%1) \n\t"
-		 "mov %%ebx, 4(%1) \n\t"
-		 "mov %%ecx, 8(%1) \n\t"
-		 "mov %%edx, 12(%1) \n\t"
-		 "popa"
-		 : : "a"(function), "S"(vec)
-		 : "memory", "cc");
+                 "cpuid \n\t"
+                 "mov %%eax, 0(%1) \n\t"
+                 "mov %%ebx, 4(%1) \n\t"
+                 "mov %%ecx, 8(%1) \n\t"
+                 "mov %%edx, 12(%1) \n\t"
+                 "popa"
+                 : : "a"(function), "c"(count), "S"(vec)
+                 : "memory", "cc");
 #endif
 
     if (eax)
@@ -1409,7 +1410,7 @@ static void host_cpuid(uint32_t function, uint32_t *eax, uint32_t *ebx,
 #endif
 }
 
-void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
+void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
                    uint32_t *eax, uint32_t *ebx,
                    uint32_t *ecx, uint32_t *edx)
 {
@@ -1434,7 +1435,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
          * actuall cpu, and say goodbye to migration between different vendors
          * is you use compatibility mode. */
         if (kvm_enabled())
-            host_cpuid(0, NULL, ebx, ecx, edx);
+            host_cpuid(0, 0, NULL, ebx, ecx, edx);
         break;
     case 1:
         *eax = env->cpuid_version;
@@ -1455,7 +1456,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
         break;
     case 4:
         /* cache info: needed for Core compatibility */
-        switch (*ecx) {
+        switch (count) {
             case 0: /* L1 dcache info */
                 *eax = 0x0000121;
                 *ebx = 0x1c0003f;
@@ -1481,7 +1482,6 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
                 *edx = 0;
                 break;
         }
-
         break;
     case 5:
         /* mwait info: needed for Core compatibility */
@@ -1526,7 +1526,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
         if (kvm_enabled()) {
             uint32_t h_eax, h_edx;
 
-            host_cpuid(0x80000001, &h_eax, NULL, NULL, &h_edx);
+            host_cpuid(index, 0, &h_eax, NULL, NULL, &h_edx);
 
             /* disable CPU features that the host does not support */
 
diff --git a/qemu/target-i386/kvm.c b/qemu/target-i386/kvm.c
index 49766e2..5de3264 100644
--- a/qemu/target-i386/kvm.c
+++ b/qemu/target-i386/kvm.c
@@ -44,13 +44,13 @@ int kvm_arch_init_vcpu(CPUState *env)
 
     cpuid_i = 0;
 
-    cpu_x86_cpuid(env, 0, &eax, &ebx, &ecx, &edx);
+    cpu_x86_cpuid(env, 0, 0, &eax, &ebx, &ecx, &edx);
     limit = eax;
 
     for (i = 0; i <= limit; i++) {
         struct kvm_cpuid_entry *c = &cpuid_data.entries[cpuid_i++];
 
-        cpu_x86_cpuid(env, i, &eax, &ebx, &ecx, &edx);
+        cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);
         c->function = i;
         c->eax = eax;
         c->ebx = ebx;
@@ -58,13 +58,13 @@ int kvm_arch_init_vcpu(CPUState *env)
         c->edx = edx;
     }
 
-    cpu_x86_cpuid(env, 0x80000000, &eax, &ebx, &ecx, &edx);
+    cpu_x86_cpuid(env, 0x80000000, 0, &eax, &ebx, &ecx, &edx);
     limit = eax;
 
     for (i = 0x80000000; i <= limit; i++) {
         struct kvm_cpuid_entry *c = &cpuid_data.entries[cpuid_i++];
 
-        cpu_x86_cpuid(env, i, &eax, &ebx, &ecx, &edx);
+        cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);
         c->function = i;
         c->eax = eax;
         c->ebx = ebx;
diff --git a/qemu/target-i386/op_helper.c b/qemu/target-i386/op_helper.c
index c2eda86..6aaa705 100644
--- a/qemu/target-i386/op_helper.c
+++ b/qemu/target-i386/op_helper.c
@@ -1913,7 +1913,7 @@ void helper_cpuid(void)
 
     helper_svm_check_intercept_param(SVM_EXIT_CPUID, 0);
 
-    cpu_x86_cpuid(env, (uint32_t)EAX, &eax, &ebx, &ecx, &edx);
+    cpu_x86_cpuid(env, (uint32_t)EAX, (uint32_t)ECX, &eax, &ebx, &ecx, &edx);
     EAX = eax;
     EBX = ebx;
     ECX = ecx;
-- 
1.6.0.6

[Qemu-devel] [PATCH] KVM: Fetch sub-leaf cpuid values for functions 4, 0xb, 0xd.

[Amit Shah]

CPUID functions 4, 0xb and 0xd have sub-leaf values which depend on the
input value of ECX. Store these values as well.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 qemu/target-i386/kvm.c |   53 +++++++++++++++++++++++++++++++++++------------
 1 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/qemu/target-i386/kvm.c b/qemu/target-i386/kvm.c
index 5de3264..b9c106e 100644
--- a/qemu/target-i386/kvm.c
+++ b/qemu/target-i386/kvm.c
@@ -36,10 +36,10 @@
 int kvm_arch_init_vcpu(CPUState *env)
 {
     struct {
-        struct kvm_cpuid cpuid;
-        struct kvm_cpuid_entry entries[100];
+        struct kvm_cpuid2 cpuid;
+        struct kvm_cpuid_entry2 entries[100];
     } __attribute__((packed)) cpuid_data;
-    uint32_t limit, i, cpuid_i;
+    uint32_t limit, i, j, cpuid_i;
     uint32_t eax, ebx, ecx, edx;
 
     cpuid_i = 0;
@@ -48,21 +48,46 @@ int kvm_arch_init_vcpu(CPUState *env)
     limit = eax;
 
     for (i = 0; i <= limit; i++) {
-        struct kvm_cpuid_entry *c = &cpuid_data.entries[cpuid_i++];
-
-        cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);
-        c->function = i;
-        c->eax = eax;
-        c->ebx = ebx;
-        c->ecx = ecx;
-        c->edx = edx;
+        struct kvm_cpuid_entry2 *c = &cpuid_data.entries[cpuid_i++];
+
+        switch (i) {
+        case 4:
+        case 0xb:
+        case 0xd:
+            for (j = 0; ; j++) {
+                cpu_x86_cpuid(env, i, j, &eax, &ebx, &ecx, &edx);
+                c->function = i;
+                c->flags = KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+                c->index = j;
+                c->eax = eax;
+                c->ebx = ebx;
+                c->ecx = ecx;
+                c->edx = edx;
+                c = &cpuid_data.entries[++cpuid_i];
+
+                if (i == 4 && eax == 0)
+                    break;
+                if (i == 0xb && !(ecx & 0xff00))
+                    break;
+                if (i == 0xd && eax == 0)
+                    break;
+            }
+            break;
+        default:
+            cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);
+            c->function = i;
+            c->eax = eax;
+            c->ebx = ebx;
+            c->ecx = ecx;
+            c->edx = edx;
+            break;
+        }
     }
-
     cpu_x86_cpuid(env, 0x80000000, 0, &eax, &ebx, &ecx, &edx);
     limit = eax;
 
     for (i = 0x80000000; i <= limit; i++) {
-        struct kvm_cpuid_entry *c = &cpuid_data.entries[cpuid_i++];
+        struct kvm_cpuid_entry2 *c = &cpuid_data.entries[cpuid_i++];
 
         cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);
         c->function = i;
@@ -74,7 +99,7 @@ int kvm_arch_init_vcpu(CPUState *env)
 
     cpuid_data.cpuid.nent = cpuid_i;
 
-    return kvm_vcpu_ioctl(env, KVM_SET_CPUID, &cpuid_data);
+    return kvm_vcpu_ioctl(env, KVM_SET_CPUID2, &cpuid_data);
 }
 
 static int kvm_has_msr_star(CPUState *env)
-- 
1.6.0.6

[Qemu-devel] [PATCH] KVM: Get all cpuid values from function 2

[Amit Shah]

cpuid function 2 can have multiple values to describe cache behaviour.
Loop till we have fetched all the values.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 qemu/target-i386/kvm.c |   26 ++++++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/qemu/target-i386/kvm.c b/qemu/target-i386/kvm.c
index b9c106e..93ff31f 100644
--- a/qemu/target-i386/kvm.c
+++ b/qemu/target-i386/kvm.c
@@ -51,6 +51,32 @@ int kvm_arch_init_vcpu(CPUState *env)
         struct kvm_cpuid_entry2 *c = &cpuid_data.entries[cpuid_i++];
 
         switch (i) {
+        case 2: {
+            /* Keep reading function 2 till all the input is received */
+            int times;
+
+            cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);
+            times = eax & 0xff;
+
+            c->function = i;
+            c->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
+            c->flags |= KVM_CPUID_FLAG_STATE_READ_NEXT;
+            c->eax = eax;
+            c->ebx = ebx;
+            c->ecx = ecx;
+            c->edx = edx;
+
+            for (j = 1; j < times; ++j) {
+                cpu_x86_cpuid(env, i, 0, &eax, &ebx, &ecx, &edx);
+                c->function = i;
+                c->flags |= KVM_CPUID_FLAG_STATEFUL_FUNC;
+                c->eax = eax;
+                c->ebx = ebx;
+                c->ecx = ecx;
+                c->edx = edx;
+            }
+            break;
+        }
         case 4:
         case 0xb:
         case 0xd:
-- 
1.6.0.6

[Qemu-devel] Re: [PATCH] KVM: CPUID takes ecx as input value for some functions

[Anthony Liguori]

Amit Shah wrote:
> The CPUID instruction takes the value of ECX as an input parameter
> in addition to the value of EAX as the count for functions 4, 0xb
> and 0xd. Make sure we pass the value to the instruction.
>
> Also convert to the qemu-style whitespace for the surrounding code.
>
> Signed-off-by: Amit Shah <amit.shah@redhat.com>
>   

Applied all, thanks.

Regards,

Anthony Liguori