On 06/10/2010 06:27 AM, Sheng Yang wrote:
This patch enable save/restore of xsave state.
Signed-off-by: Sheng Yang<[email protected]>
---
Documentation/kvm/api.txt | 76 ++++++++++++++++++++++++++++++
arch/x86/include/asm/kvm.h | 24 ++++++++++
arch/x86/kvm/x86.c | 110 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/kvm.h | 12 +++++
4 files changed, 222 insertions(+), 0 deletions(-)
diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index 159b4ef..cb0afa2 100644
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -922,6 +922,82 @@ Define which vcpu is the Bootstrap Processor (BSP).
Values are the same
as the vcpu id in KVM_CREATE_VCPU. If this ioctl is not called, the default
is vcpu 0.
+4.41 KVM_GET_XSAVE
+
+Capability: KVM_CAP_XSAVE
+Architectures: x86
+Type: vcpu ioctl
+Parameters: struct kvm_xsave (out)
+Returns: 0 on success, -1 on error
+
+struct kvm_xsave {
+ __u32 size;
+ __u32 region[1000];
+};
+
+This ioctl would copy current vcpu's xsave struct to the userspace.
How is size interpreted?
I think we can leave it out since it is implied by the xsave header.
+/* for KVM_CAP_XSAVE */
+struct kvm_xsave {
+ __u32 size;
+ __u32 reserved[3];
+ __u32 region[1020];
+};
That's different from the documentation.
+
+#define KVM_MAX_XCRS 1
Needs to be much bigger for future compatibility, since it's part of the
ABI.
@@ -2373,6 +2375,60 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct
kvm_vcpu *vcpu,
return 0;
}
+static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu,
+ struct kvm_xsave *guest_xsave)
+{
+ u32 size;
+
+ if (cpu_has_xsave)
+ size = sizeof(struct xsave_struct);
+ else
+ size = sizeof(struct i387_fxsave_struct);
+
+ guest_xsave->size = size;
+ memcpy(guest_xsave->region,&vcpu->arch.guest_fpu.state->xsave, size);
If !cpu_has_xsave, we can create a fake xsave header that says we have
the fpu and sse, so userspace doesn't have to look at size.
You're memcpy()ing state->xsave unconditionally, even if
!cpu_has_xsave. That works, but it's cleaner to access the ->fxsave member.
+
+static void kvm_vcpu_ioctl_x86_get_xcrs(struct kvm_vcpu *vcpu,
+ struct kvm_xcrs *guest_xcrs)
+{
+ guest_xcrs->nr_xcrs = 1;
+ guest_xcrs->flags = 0;
+ guest_xcrs->xcrs[0].value = vcpu->arch.xcr0;
+}
guest_xcrs[0].xcr = ...
What if !cpu_has_xsave? Probably should set nr_xcrs = 0.
+
+static int kvm_vcpu_ioctl_x86_set_xcrs(struct kvm_vcpu *vcpu,
+ struct kvm_xcrs *guest_xcrs)
+{
+ if (guest_xcrs->nr_xcrs< 1)
+ return 1;
Not really needed.
+
+ /* Userspace may override the initial value of xcr0... */
+ if (guest_xcrs->xcrs[0].value != 0) {
Why check the value? What about checking the xcrs[].xcr?
+ vcpu->arch.xcr0 = guest_xcrs->xcrs[0].value;
+ vcpu->guest_xcr0_loaded = 0;
+ }
Need to loop over the array. Also, call kvm_set_xcr() to get checks to
be performed.
--
error compiling committee.c: too many arguments to function
--
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