Re: [Qemu-devel] [PATCH v2 3/4] target-i386: Allow changing of Hypervisor CPUIDs.

[Marcelo Tosatti]

On Thu, Sep 13, 2012 at 02:43:55PM -0400, Don Slutz wrote:
> On 09/12/12 13:55, Marcelo Tosatti wrote:
> >The problem with integrating this is that it has little or
> >no assurance from documentation. The Linux kernel source is a good
> >source, then say "accordingly to VMWare guest support code in version xyz"
> >in the changelog.
> I will work on getting a list of the documentation and sources used
> to generate this.
> >
> >Also extracting this information in a text file (or comment in the code)
> >would be better than just adding code.
> I am not sure what information you are talking about here.  Are you
> asking about the known "Hypervisor CPUIDs", or what a lot of Linux
> version look at to determine the Hypervisor they are on, or
> something else?

Just a summary of where you got the info from.

> >On Tue, Sep 11, 2012 at 10:07:46AM -0400, Don Slutz wrote:
> >>This is primarily done so that the guest will think it is running
> >>under vmware when hypervisor-vendor=vmware is specified as a
> >>property of a cpu.
> >>
> >>Signed-off-by: Don Slutz <address@hidden>
> >>---
> >>  target-i386/cpu.c |  214 
> >> +++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>  target-i386/cpu.h |   21 +++++
> >>  target-i386/kvm.c |   33 +++++++--
> >>  3 files changed, 262 insertions(+), 6 deletions(-)
> >>
> >>diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> >>index 5f9866a..9f1f390 100644
> >>--- a/target-i386/cpu.c
> >>+++ b/target-i386/cpu.c
> >>@@ -1135,6 +1135,36 @@ static void x86_cpuid_set_model_id(Object *obj, 
> >>const char *model_id,
> >>      }
> >>  }
> >>+static void x86_cpuid_set_vmware_extra(Object *obj)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+
> >>+    if ((cpu->env.tsc_khz != 0) &&
> >>+        (cpu->env.cpuid_hv_level == CPUID_HV_LEVEL_VMARE_4) &&
> >>+        (cpu->env.cpuid_hv_vendor1 == CPUID_HV_VENDOR_VMWARE_1) &&
> >>+        (cpu->env.cpuid_hv_vendor2 == CPUID_HV_VENDOR_VMWARE_2) &&
> >>+        (cpu->env.cpuid_hv_vendor3 == CPUID_HV_VENDOR_VMWARE_3)) {
> >>+        const uint32_t apic_khz = 1000000L;
> >>+
> >>+        /*
> >>+         * From article.gmane.org/gmane.comp.emulators.kvm.devel/22643
> >>+         *
> >>+         *    Leaf 0x40000010, Timing Information.
> >>+         *
> >>+         *    VMware has defined the first generic leaf to provide timing
> >>+         *    information.  This leaf returns the current TSC frequency and
> >>+         *    current Bus frequency in kHz.
> >>+         *
> >>+         *    # EAX: (Virtual) TSC frequency in kHz.
> >>+         *    # EBX: (Virtual) Bus (local apic timer) frequency in kHz.
> >>+         *    # ECX, EDX: RESERVED (Per above, reserved fields are set to 
> >>zero).
> >>+         */
> >>+        cpu->env.cpuid_hv_extra = 0x40000010;
> >>+        cpu->env.cpuid_hv_extra_a = (uint32_t)cpu->env.tsc_khz;
> >>+        cpu->env.cpuid_hv_extra_b = apic_khz;
> >>+    }
> >>+}
> >What happens in case you migrate the vmware guest to a host
> >with different frequency? How is that transmitted to the
> >vmware-guest-running-on-kvm ? Or is migration not supported?
> As far as I know, it would be the same as for a non-vmware guest.
> http://lists.nongnu.org/archive/html/qemu-devel/2011-07/msg01656.html
> is related to this.
> 
> I did not look to see if this has been done since then.

No it has not, but something similar will be, see:

http://www.spinics.net/lists/kvm/msg79719.html

Yeah alright.

> All this change does is to allow the guest to "read" the
> tsc-frequency instead of trying to calculate it.
> 
> I will look into the current state of migration when tsc_freq=X is
> specified.  The machine I have been doing most of the testing on
> (Intel Xeon E3-1260L) when I add tsc_freq=2.0G or tsc_freq=2.4G, the
> guest does not see any difference in accel=kvm.

Yeah i think you can ignore it.

> >>+static void x86_cpuid_set_hv_level(Object *obj, Visitor *v, void *opaque,
> >>+                                const char *name, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+    uint32_t value;
> >>+
> >>+    visit_type_uint32(v, &value, name, errp);
> >>+    if (error_is_set(errp)) {
> >>+        return;
> >>+    }
> >>+
> >>+    if ((value != 0) && (value < 0x40000000)) {
> >>+        value += 0x40000000;
> >>+    }
> >>+    cpu->env.cpuid_hv_level = value;
> >>+}
> >>+
> >>+static char *x86_cpuid_get_hv_vendor(Object *obj, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+    CPUX86State *env = &cpu->env;
> >>+    char *value;
> >>+    int i;
> >>+
> >>+    value = (char *)g_malloc(CPUID_VENDOR_SZ + 1);
> >>+    for (i = 0; i < 4; i++) {
> >>+        value[i + 0] = env->cpuid_hv_vendor1 >> (8 * i);
> >>+        value[i + 4] = env->cpuid_hv_vendor2 >> (8 * i);
> >>+        value[i + 8] = env->cpuid_hv_vendor3 >> (8 * i);
> >>+    }
> >>+    value[CPUID_VENDOR_SZ] = '\0';
> >>+
> >>+    /* Convert known names */
> >>+    if (!strcmp(value, CPUID_HV_VENDOR_VMWARE)) {
> >>+        if (env->cpuid_hv_level == CPUID_HV_LEVEL_VMARE_4) {
> >>+            pstrcpy(value, sizeof(value), "vmware4");
> >>+        } else if (env->cpuid_hv_level == CPUID_HV_LEVEL_VMARE_3) {
> >>+            pstrcpy(value, sizeof(value), "vmware3");
> >>+        }
> >>+    } else if (!strcmp(value, CPUID_HV_VENDOR_XEN) &&
> >>+               env->cpuid_hv_level == CPUID_HV_LEVEL_XEN) {
> >>+        pstrcpy(value, sizeof(value), "xen");
> >>+    } else if (!strcmp(value, CPUID_HV_VENDOR_KVM) &&
> >>+               env->cpuid_hv_level == 0) {
> >>+        pstrcpy(value, sizeof(value), "kvm");
> >>+    }
> >>+    return value;
> >>+}
> >>+
> >>+static void x86_cpuid_set_hv_vendor(Object *obj, const char *value,
> >>+                                     Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+    CPUX86State *env = &cpu->env;
> >>+    int i;
> >>+    char adj_value[CPUID_VENDOR_SZ + 1];
> >>+
> >>+    memset(adj_value, 0, sizeof(adj_value));
> >>+
> >>+    /* Convert known names */
> >>+    if (!strcmp(value, "vmware") || !strcmp(value, "vmware4")) {
> >>+        if (env->cpuid_hv_level == 0) {
> >>+            env->cpuid_hv_level = CPUID_HV_LEVEL_VMARE_4;
> >>+        }
> >>+        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_VMWARE);
> >>+    } else if (!strcmp(value, "vmware3")) {
> >>+        if (env->cpuid_hv_level == 0) {
> >>+            env->cpuid_hv_level = CPUID_HV_LEVEL_VMARE_3;
> >>+        }
> >>+        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_VMWARE);
> >>+    } else if (!strcmp(value, "xen")) {
> >>+        if (env->cpuid_hv_level == 0) {
> >>+            env->cpuid_hv_level = CPUID_HV_LEVEL_XEN;
> >>+        }
> >>+        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_XEN);
> >>+    } else if (!strcmp(value, "kvm")) {
> >>+        pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_KVM);
> >>+    } else {
> >>+        pstrcpy(adj_value, sizeof(adj_value), value);
> >>+    }
> >>+
> >>+    env->cpuid_hv_vendor1 = 0;
> >>+    env->cpuid_hv_vendor2 = 0;
> >>+    env->cpuid_hv_vendor3 = 0;
> >>+    for (i = 0; i < 4; i++) {
> >>+        env->cpuid_hv_vendor1 |= ((uint8_t)adj_value[i + 0]) << (8 * i);
> >>+        env->cpuid_hv_vendor2 |= ((uint8_t)adj_value[i + 4]) << (8 * i);
> >>+        env->cpuid_hv_vendor3 |= ((uint8_t)adj_value[i + 8]) << (8 * i);
> >>+    }
> >>+    x86_cpuid_set_vmware_extra(obj);
> >>+}
> >>+
> >>+static void x86_cpuid_get_hv_extra(Object *obj, Visitor *v, void *opaque,
> >>+                                const char *name, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+
> >>+    visit_type_uint32(v, &cpu->env.cpuid_hv_extra, name, errp);
> >>+}
> >>+
> >>+static void x86_cpuid_set_hv_extra(Object *obj, Visitor *v, void *opaque,
> >>+                                const char *name, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+    uint32_t value;
> >>+
> >>+    visit_type_uint32(v, &value, name, errp);
> >>+    if (error_is_set(errp)) {
> >>+        return;
> >>+    }
> >>+
> >>+    if ((value != 0) && (value < 0x40000000)) {
> >>+        value += 0x40000000;
> >>+    }
> >>+    cpu->env.cpuid_hv_extra = value;
> >>+}
> >>+
> >>+static void x86_cpuid_get_hv_extra_a(Object *obj, Visitor *v, void *opaque,
> >>+                                const char *name, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+
> >>+    visit_type_uint32(v, &cpu->env.cpuid_hv_extra_a, name, errp);
> >>+}
> >>+
> >>+static void x86_cpuid_set_hv_extra_a(Object *obj, Visitor *v, void *opaque,
> >>+                                const char *name, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+
> >>+    visit_type_uint32(v, &cpu->env.cpuid_hv_extra_a, name, errp);
> >>+}
> >>+
> >>+static void x86_cpuid_get_hv_extra_b(Object *obj, Visitor *v, void *opaque,
> >>+                                const char *name, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+
> >>+    visit_type_uint32(v, &cpu->env.cpuid_hv_extra_b, name, errp);
> >>+}
> >>+
> >>+static void x86_cpuid_set_hv_extra_b(Object *obj, Visitor *v, void *opaque,
> >>+                                const char *name, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+
> >>+    visit_type_uint32(v, &cpu->env.cpuid_hv_extra_b, name, errp);
> >>  }
> >>  #if !defined(CONFIG_USER_ONLY)
> >>+static void x86_set_hyperv(Object *obj, Error **errp)
> >>+{
> >>+    X86CPU *cpu = X86_CPU(obj);
> >>+
> >>+    cpu->env.cpuid_hv_level = HYPERV_CPUID_MIN;
> >>+    x86_cpuid_set_hv_vendor(obj, "Microsoft Hv", errp);
> >>+}
> >>+
> >>  static void x86_get_hv_spinlocks(Object *obj, Visitor *v, void *opaque,
> >>                                   const char *name, Error **errp)
> >>  {
> >>@@ -1189,6 +1385,7 @@ static void x86_set_hv_spinlocks(Object *obj, Visitor 
> >>*v, void *opaque,
> >>          return;
> >>      }
> >>      hyperv_set_spinlock_retries(value);
> >>+    x86_set_hyperv(obj, errp);
> >>  }
> >>  static void x86_get_hv_relaxed(Object *obj, Visitor *v, void *opaque,
> >>@@ -1209,6 +1406,7 @@ static void x86_set_hv_relaxed(Object *obj, Visitor 
> >>*v, void *opaque,
> >>          return;
> >>      }
> >>      hyperv_enable_relaxed_timing(value);
> >>+    x86_set_hyperv(obj, errp);
> >>  }
> >This seems unrelated to the rest of the patch?
> The new call to x86_set_hyperv() is how the 1st change to
> target-i386/kvm.c still does the same thing as before.
> >
> >>  static void x86_get_hv_vapic(Object *obj, Visitor *v, void *opaque,
> >>@@ -1229,6 +1427,7 @@ static void x86_set_hv_vapic(Object *obj, Visitor *v, 
> >>void *opaque,
> >>          return;
> >>      }
> >>      hyperv_enable_vapic_recommended(value);
> >>+    x86_set_hyperv(obj, errp);
> >>  }
> >>  #endif
> >>@@ -2061,6 +2260,21 @@ static void x86_cpu_initfn(Object *obj)
> >>      object_property_add(obj, "enforce", "bool",
> >>                          x86_cpuid_get_enforce,
> >>                          x86_cpuid_set_enforce, NULL, NULL, NULL);
> >>+    object_property_add(obj, "hypervisor-level", "int",
> >>+                        x86_cpuid_get_hv_level,
> >>+                        x86_cpuid_set_hv_level, NULL, NULL, NULL);
> >>+    object_property_add_str(obj, "hypervisor-vendor",
> >>+                            x86_cpuid_get_hv_vendor,
> >>+                            x86_cpuid_set_hv_vendor, NULL);
> >>+    object_property_add(obj, "hypervisor-extra", "int",
> >>+                        x86_cpuid_get_hv_extra,
> >>+                        x86_cpuid_set_hv_extra, NULL, NULL, NULL);
> >>+    object_property_add(obj, "hypervisor-extra-a", "int",
> >>+                        x86_cpuid_get_hv_extra_a,
> >>+                        x86_cpuid_set_hv_extra_a, NULL, NULL, NULL);
> >>+    object_property_add(obj, "hypervisor-extra-b", "int",
> >>+                        x86_cpuid_get_hv_extra_b,
> >>+                        x86_cpuid_set_hv_extra_b, NULL, NULL, NULL);
> >>  #if !defined(CONFIG_USER_ONLY)
> >>      object_property_add(obj, "hv_spinlocks", "int",
> >>                          x86_get_hv_spinlocks,
> >>diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> >>index 5265c5a..a2d3588 100644
> >>--- a/target-i386/cpu.h
> >>+++ b/target-i386/cpu.h
> >>@@ -488,6 +488,18 @@
> >>  #define CPUID_VENDOR_VIA   "CentaurHauls"
> >>+#define CPUID_HV_VENDOR_VMWARE_1 0x61774d56 /* "VMwa" */
> >>+#define CPUID_HV_VENDOR_VMWARE_2 0x4d566572 /* "reVM" */
> >>+#define CPUID_HV_VENDOR_VMWARE_3 0x65726177 /* "ware" */
> >>+#define CPUID_HV_VENDOR_VMWARE "VMwareVMware"
> >>+#define CPUID_HV_LEVEL_VMARE_3 0x40000002
> >>+#define CPUID_HV_LEVEL_VMARE_4 0x40000010
> >>+
> >>+#define CPUID_HV_VENDOR_XEN "XenVMMXenVMM"
> >>+#define CPUID_HV_LEVEL_XEN  0x40000002
> >>+
> >>+#define CPUID_HV_VENDOR_KVM "KVMKVMKVM"
> >>+
> >>  #define CPUID_MWAIT_IBE     (1 << 1) /* Interrupts can exit capability */
> >>  #define CPUID_MWAIT_EMX     (1 << 0) /* enumeration supported */
> >>@@ -782,6 +794,15 @@ typedef struct CPUX86State {
> >>      uint32_t cpuid_ext4_features;
> >>      /* Flags from CPUID[EAX=7,ECX=0].EBX */
> >>      uint32_t cpuid_7_0_ebx;
> >>+    /* Hypervisor CPUIDs */
> >>+    uint32_t cpuid_hv_level;
> >>+    uint32_t cpuid_hv_vendor1;
> >>+    uint32_t cpuid_hv_vendor2;
> >>+    uint32_t cpuid_hv_vendor3;
> >>+    /* VMware extra data */
> >>+    uint32_t cpuid_hv_extra;
> >>+    uint32_t cpuid_hv_extra_a;
> >>+    uint32_t cpuid_hv_extra_b;
> >>      /* MTRRs */
> >>      uint64_t mtrr_fixed[11];
> >>diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> >>index 895d848..17c72bc 100644
> >>--- a/target-i386/kvm.c
> >>+++ b/target-i386/kvm.c
> >>@@ -389,16 +389,18 @@ int kvm_arch_init_vcpu(CPUX86State *env)
> >>      c = &cpuid_data.entries[cpuid_i++];
> >>      memset(c, 0, sizeof(*c));
> >>      c->function = KVM_CPUID_SIGNATURE;
> >>-    if (!hyperv_enabled()) {
> >>+    if (env->cpuid_hv_level == 0) {
> >>          memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> >>          c->eax = 0;
> >>+        c->ebx = signature[0];
> >>+        c->ecx = signature[1];
> >>+        c->edx = signature[2];
> >>      } else {
> >>-        memcpy(signature, "Microsoft Hv", 12);
> >>-        c->eax = HYPERV_CPUID_MIN;
> >>+        c->eax = env->cpuid_hv_level;
> >>+        c->ebx = env->cpuid_hv_vendor1;
> >>+        c->ecx = env->cpuid_hv_vendor2;
> >>+        c->edx = env->cpuid_hv_vendor3;
> >>      }
> >>-    c->ebx = signature[0];
> >>-    c->ecx = signature[1];
> >>-    c->edx = signature[2];
> >>      c = &cpuid_data.entries[cpuid_i++];
> >>      memset(c, 0, sizeof(*c));
> >>@@ -452,6 +454,25 @@ int kvm_arch_init_vcpu(CPUX86State *env)
> >>          c->ebx = signature[0];
> >>          c->ecx = signature[1];
> >>          c->edx = signature[2];
> >>+    } else if (env->cpuid_hv_level > 0) {
> >>+        for (i = KVM_CPUID_FEATURES + 1; i <= env->cpuid_hv_level; i++) {
> >>+            c = &cpuid_data.entries[cpuid_i++];
> >>+            memset(c, 0, sizeof(*c));
> >>+            c->function = i;
> >>+            if (i == env->cpuid_hv_extra) {
> >>+                c->eax = env->cpuid_hv_extra_a;
> >>+                c->ebx = env->cpuid_hv_extra_b;
> >>+            }
> >>+        }
> >>+
> >>+        c = &cpuid_data.entries[cpuid_i++];
> >>+        memset(c, 0, sizeof(*c));
> >>+        c->function = KVM_CPUID_SIGNATURE_NEXT;
> >>+        memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> >>+        c->eax = 0;
> >>+        c->ebx = signature[0];
> >>+        c->ecx = signature[1];
> >>+        c->edx = signature[2];
> >>      }
> >>      has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
> >
> >Its one big patch, better split in logically correlated patches
> >(with better changelog). This would help reviewers.
> Will re-work into a set of smaller changes.
>    -Don

OK then.