* [Qemu-devel] [PATCH] kvm: Enable -cpu option to hide KVM
@ 2014-06-02 17:28 Alex Williamson
2014-06-02 19:09 ` Bandan Das
2014-06-03 9:21 ` Paolo Bonzini
0 siblings, 2 replies; 4+ messages in thread
From: Alex Williamson @ 2014-06-02 17:28 UTC (permalink / raw)
To: qemu-devel; +Cc: pbonzini, kvm
The latest Nvidia driver (337.88) specifically checks for KVM as the
hypervisor and reports Code 43 for the driver in a Windows guest when
found. Removing or changing the KVM signature is sufficient for the
driver to load and work. This patch adds an option to easily allow
the KVM hypervisor signature to be hidden using '-cpu kvm=off'. We
continue to expose KVM via the cpuid value by default. The state of
this option does not supercede or replace -enable-kvm or the accel=kvm
machine option. This only changes the visibility of KVM to the guest
and paravirtual features specifically tied to the KVM cpuid.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
target-i386/cpu-qom.h | 1 +
target-i386/cpu.c | 1 +
target-i386/kvm.c | 28 +++++++++++++++-------------
3 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
index e9b3d57..0808cfc 100644
--- a/target-i386/cpu-qom.h
+++ b/target-i386/cpu-qom.h
@@ -87,6 +87,7 @@ typedef struct X86CPU {
bool hyperv_time;
bool check_cpuid;
bool enforce_cpuid;
+ bool expose_kvm;
/* if true the CPUID code directly forward host cache leaves to the guest */
bool cache_info_passthrough;
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 042a48d..cbf1d97 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -2792,6 +2792,7 @@ static Property x86_cpu_properties[] = {
DEFINE_PROP_BOOL("hv-time", X86CPU, hyperv_time, false),
DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, false),
DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false),
+ DEFINE_PROP_BOOL("kvm", X86CPU, expose_kvm, true),
DEFINE_PROP_END_OF_LIST()
};
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 0d894ef..b2295d2 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -528,23 +528,25 @@ int kvm_arch_init_vcpu(CPUState *cs)
has_msr_hv_hypercall = true;
}
- memcpy(signature, "KVMKVMKVM\0\0\0", 12);
- c = &cpuid_data.entries[cpuid_i++];
- c->function = KVM_CPUID_SIGNATURE | kvm_base;
- c->eax = 0;
- c->ebx = signature[0];
- c->ecx = signature[1];
- c->edx = signature[2];
+ if (cpu->expose_kvm) {
+ memcpy(signature, "KVMKVMKVM\0\0\0", 12);
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = KVM_CPUID_SIGNATURE | kvm_base;
+ c->eax = 0;
+ c->ebx = signature[0];
+ c->ecx = signature[1];
+ c->edx = signature[2];
- c = &cpuid_data.entries[cpuid_i++];
- c->function = KVM_CPUID_FEATURES | kvm_base;
- c->eax = env->features[FEAT_KVM];
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = KVM_CPUID_FEATURES | kvm_base;
+ c->eax = env->features[FEAT_KVM];
- has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
+ has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
- has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
+ has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
- has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
+ has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
+ }
cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused);
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH] kvm: Enable -cpu option to hide KVM
2014-06-02 17:28 [Qemu-devel] [PATCH] kvm: Enable -cpu option to hide KVM Alex Williamson
@ 2014-06-02 19:09 ` Bandan Das
2014-06-02 19:17 ` Alex Williamson
2014-06-03 9:21 ` Paolo Bonzini
1 sibling, 1 reply; 4+ messages in thread
From: Bandan Das @ 2014-06-02 19:09 UTC (permalink / raw)
To: Alex Williamson; +Cc: pbonzini, qemu-devel, kvm
Alex Williamson <alex.williamson@redhat.com> writes:
> The latest Nvidia driver (337.88) specifically checks for KVM as the
> hypervisor and reports Code 43 for the driver in a Windows guest when
> found. Removing or changing the KVM signature is sufficient for the
> driver to load and work. This patch adds an option to easily allow
> the KVM hypervisor signature to be hidden using '-cpu kvm=off'. We
> continue to expose KVM via the cpuid value by default. The state of
> this option does not supercede or replace -enable-kvm or the accel=kvm
> machine option. This only changes the visibility of KVM to the guest
> and paravirtual features specifically tied to the KVM cpuid.
>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> target-i386/cpu-qom.h | 1 +
> target-i386/cpu.c | 1 +
> target-i386/kvm.c | 28 +++++++++++++++-------------
> 3 files changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
> index e9b3d57..0808cfc 100644
> --- a/target-i386/cpu-qom.h
> +++ b/target-i386/cpu-qom.h
> @@ -87,6 +87,7 @@ typedef struct X86CPU {
> bool hyperv_time;
> bool check_cpuid;
> bool enforce_cpuid;
> + bool expose_kvm;
>
> /* if true the CPUID code directly forward host cache leaves to the guest */
> bool cache_info_passthrough;
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 042a48d..cbf1d97 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -2792,6 +2792,7 @@ static Property x86_cpu_properties[] = {
> DEFINE_PROP_BOOL("hv-time", X86CPU, hyperv_time, false),
> DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, false),
> DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false),
> + DEFINE_PROP_BOOL("kvm", X86CPU, expose_kvm, true),
> DEFINE_PROP_END_OF_LIST()
> };
>
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 0d894ef..b2295d2 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -528,23 +528,25 @@ int kvm_arch_init_vcpu(CPUState *cs)
> has_msr_hv_hypercall = true;
> }
>
> - memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> - c = &cpuid_data.entries[cpuid_i++];
> - c->function = KVM_CPUID_SIGNATURE | kvm_base;
> - c->eax = 0;
> - c->ebx = signature[0];
> - c->ecx = signature[1];
> - c->edx = signature[2];
> + if (cpu->expose_kvm) {
> + memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> + c = &cpuid_data.entries[cpuid_i++];
> + c->function = KVM_CPUID_SIGNATURE | kvm_base;
> + c->eax = 0;
> + c->ebx = signature[0];
> + c->ecx = signature[1];
> + c->edx = signature[2];
>
> - c = &cpuid_data.entries[cpuid_i++];
> - c->function = KVM_CPUID_FEATURES | kvm_base;
> - c->eax = env->features[FEAT_KVM];
> + c = &cpuid_data.entries[cpuid_i++];
> + c->function = KVM_CPUID_FEATURES | kvm_base;
> + c->eax = env->features[FEAT_KVM];
>
> - has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
> + has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
>
> - has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
> + has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
>
> - has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
> + has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
Does this mean that we don't expose these features if kvm=off is
specified ?
> + }
>
> cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused);
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH] kvm: Enable -cpu option to hide KVM
2014-06-02 19:09 ` Bandan Das
@ 2014-06-02 19:17 ` Alex Williamson
0 siblings, 0 replies; 4+ messages in thread
From: Alex Williamson @ 2014-06-02 19:17 UTC (permalink / raw)
To: Bandan Das; +Cc: pbonzini, qemu-devel, kvm
On Mon, 2014-06-02 at 15:09 -0400, Bandan Das wrote:
> Alex Williamson <alex.williamson@redhat.com> writes:
>
> > The latest Nvidia driver (337.88) specifically checks for KVM as the
> > hypervisor and reports Code 43 for the driver in a Windows guest when
> > found. Removing or changing the KVM signature is sufficient for the
> > driver to load and work. This patch adds an option to easily allow
> > the KVM hypervisor signature to be hidden using '-cpu kvm=off'. We
> > continue to expose KVM via the cpuid value by default. The state of
> > this option does not supercede or replace -enable-kvm or the accel=kvm
> > machine option. This only changes the visibility of KVM to the guest
> > and paravirtual features specifically tied to the KVM cpuid.
> >
> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> > ---
> > target-i386/cpu-qom.h | 1 +
> > target-i386/cpu.c | 1 +
> > target-i386/kvm.c | 28 +++++++++++++++-------------
> > 3 files changed, 17 insertions(+), 13 deletions(-)
> >
> > diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
> > index e9b3d57..0808cfc 100644
> > --- a/target-i386/cpu-qom.h
> > +++ b/target-i386/cpu-qom.h
> > @@ -87,6 +87,7 @@ typedef struct X86CPU {
> > bool hyperv_time;
> > bool check_cpuid;
> > bool enforce_cpuid;
> > + bool expose_kvm;
> >
> > /* if true the CPUID code directly forward host cache leaves to the guest */
> > bool cache_info_passthrough;
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index 042a48d..cbf1d97 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -2792,6 +2792,7 @@ static Property x86_cpu_properties[] = {
> > DEFINE_PROP_BOOL("hv-time", X86CPU, hyperv_time, false),
> > DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, false),
> > DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false),
> > + DEFINE_PROP_BOOL("kvm", X86CPU, expose_kvm, true),
> > DEFINE_PROP_END_OF_LIST()
> > };
> >
> > diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> > index 0d894ef..b2295d2 100644
> > --- a/target-i386/kvm.c
> > +++ b/target-i386/kvm.c
> > @@ -528,23 +528,25 @@ int kvm_arch_init_vcpu(CPUState *cs)
> > has_msr_hv_hypercall = true;
> > }
> >
> > - memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> > - c = &cpuid_data.entries[cpuid_i++];
> > - c->function = KVM_CPUID_SIGNATURE | kvm_base;
> > - c->eax = 0;
> > - c->ebx = signature[0];
> > - c->ecx = signature[1];
> > - c->edx = signature[2];
> > + if (cpu->expose_kvm) {
> > + memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> > + c = &cpuid_data.entries[cpuid_i++];
> > + c->function = KVM_CPUID_SIGNATURE | kvm_base;
> > + c->eax = 0;
> > + c->ebx = signature[0];
> > + c->ecx = signature[1];
> > + c->edx = signature[2];
> >
> > - c = &cpuid_data.entries[cpuid_i++];
> > - c->function = KVM_CPUID_FEATURES | kvm_base;
> > - c->eax = env->features[FEAT_KVM];
> > + c = &cpuid_data.entries[cpuid_i++];
> > + c->function = KVM_CPUID_FEATURES | kvm_base;
> > + c->eax = env->features[FEAT_KVM];
> >
> > - has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
> > + has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
> >
> > - has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
> > + has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
> >
> > - has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
> > + has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
> Does this mean that we don't expose these features if kvm=off is
> specified ?
Correct, the guest would only learn about them via the bits in this
cpuid return value, so it should not be making use of them when kvm=off.
Thanks,
Alex
>
> > + }
> >
> > cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused);
> >
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Qemu-devel] [PATCH] kvm: Enable -cpu option to hide KVM
2014-06-02 17:28 [Qemu-devel] [PATCH] kvm: Enable -cpu option to hide KVM Alex Williamson
2014-06-02 19:09 ` Bandan Das
@ 2014-06-03 9:21 ` Paolo Bonzini
1 sibling, 0 replies; 4+ messages in thread
From: Paolo Bonzini @ 2014-06-03 9:21 UTC (permalink / raw)
To: Alex Williamson, qemu-devel; +Cc: kvm
Il 02/06/2014 19:28, Alex Williamson ha scritto:
> The latest Nvidia driver (337.88) specifically checks for KVM as the
> hypervisor and reports Code 43 for the driver in a Windows guest when
> found. Removing or changing the KVM signature is sufficient for the
> driver to load and work. This patch adds an option to easily allow
> the KVM hypervisor signature to be hidden using '-cpu kvm=off'. We
> continue to expose KVM via the cpuid value by default. The state of
> this option does not supercede or replace -enable-kvm or the accel=kvm
> machine option. This only changes the visibility of KVM to the guest
> and paravirtual features specifically tied to the KVM cpuid.
>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> target-i386/cpu-qom.h | 1 +
> target-i386/cpu.c | 1 +
> target-i386/kvm.c | 28 +++++++++++++++-------------
> 3 files changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/target-i386/cpu-qom.h b/target-i386/cpu-qom.h
> index e9b3d57..0808cfc 100644
> --- a/target-i386/cpu-qom.h
> +++ b/target-i386/cpu-qom.h
> @@ -87,6 +87,7 @@ typedef struct X86CPU {
> bool hyperv_time;
> bool check_cpuid;
> bool enforce_cpuid;
> + bool expose_kvm;
>
> /* if true the CPUID code directly forward host cache leaves to the guest */
> bool cache_info_passthrough;
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index 042a48d..cbf1d97 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -2792,6 +2792,7 @@ static Property x86_cpu_properties[] = {
> DEFINE_PROP_BOOL("hv-time", X86CPU, hyperv_time, false),
> DEFINE_PROP_BOOL("check", X86CPU, check_cpuid, false),
> DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false),
> + DEFINE_PROP_BOOL("kvm", X86CPU, expose_kvm, true),
> DEFINE_PROP_END_OF_LIST()
> };
>
> diff --git a/target-i386/kvm.c b/target-i386/kvm.c
> index 0d894ef..b2295d2 100644
> --- a/target-i386/kvm.c
> +++ b/target-i386/kvm.c
> @@ -528,23 +528,25 @@ int kvm_arch_init_vcpu(CPUState *cs)
> has_msr_hv_hypercall = true;
> }
>
> - memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> - c = &cpuid_data.entries[cpuid_i++];
> - c->function = KVM_CPUID_SIGNATURE | kvm_base;
> - c->eax = 0;
> - c->ebx = signature[0];
> - c->ecx = signature[1];
> - c->edx = signature[2];
> + if (cpu->expose_kvm) {
> + memcpy(signature, "KVMKVMKVM\0\0\0", 12);
> + c = &cpuid_data.entries[cpuid_i++];
> + c->function = KVM_CPUID_SIGNATURE | kvm_base;
> + c->eax = 0;
> + c->ebx = signature[0];
> + c->ecx = signature[1];
> + c->edx = signature[2];
>
> - c = &cpuid_data.entries[cpuid_i++];
> - c->function = KVM_CPUID_FEATURES | kvm_base;
> - c->eax = env->features[FEAT_KVM];
> + c = &cpuid_data.entries[cpuid_i++];
> + c->function = KVM_CPUID_FEATURES | kvm_base;
> + c->eax = env->features[FEAT_KVM];
>
> - has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
> + has_msr_async_pf_en = c->eax & (1 << KVM_FEATURE_ASYNC_PF);
>
> - has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
> + has_msr_pv_eoi_en = c->eax & (1 << KVM_FEATURE_PV_EOI);
>
> - has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
> + has_msr_kvm_steal_time = c->eax & (1 << KVM_FEATURE_STEAL_TIME);
> + }
>
> cpu_x86_cpuid(env, 0, 0, &limit, &unused, &unused, &unused);
>
>
Applying to uq/master, thanks.
Paolo
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-06-03 9:21 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-06-02 17:28 [Qemu-devel] [PATCH] kvm: Enable -cpu option to hide KVM Alex Williamson
2014-06-02 19:09 ` Bandan Das
2014-06-02 19:17 ` Alex Williamson
2014-06-03 9:21 ` Paolo Bonzini
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).