1 files changed, 83 insertions, 7 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 08b5657e57ed..c259814200bd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3132,15 +3132,89 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu,
         return 0;
 }
 
+#define XSTATE_COMPACTION_ENABLED (1ULL << 63)
+
+static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu)
+{
+        struct xsave_struct *xsave = &vcpu->arch.guest_fpu.state->xsave;
+        u64 xstate_bv = xsave->xsave_hdr.xstate_bv;
+        u64 valid;
+
+        /*
+         * Copy legacy XSAVE area, to avoid complications with CPUID
+         * leaves 0 and 1 in the loop below.
+         */
+        memcpy(dest, xsave, XSAVE_HDR_OFFSET);
+
+        /* Set XSTATE_BV */
+        *(u64 *)(dest + XSAVE_HDR_OFFSET) = xstate_bv;
+
+        /*
+         * Copy each region from the possibly compacted offset to the
+         * non-compacted offset.
+         */
+        valid = xstate_bv & ~XSTATE_FPSSE;
+        while (valid) {
+                u64 feature = valid & -valid;
+                int index = fls64(feature) - 1;
+                void *src = get_xsave_addr(xsave, feature);
+
+                if (src) {
+                        u32 size, offset, ecx, edx;
+                        cpuid_count(XSTATE_CPUID, index,
+                                    &size, &offset, &ecx, &edx);
+                        memcpy(dest + offset, src, size);
+                }
+
+                valid -= feature;
+        }
+}
+
+static void load_xsave(struct kvm_vcpu *vcpu, u8 *src)
+{
+        struct xsave_struct *xsave = &vcpu->arch.guest_fpu.state->xsave;
+        u64 xstate_bv = *(u64 *)(src + XSAVE_HDR_OFFSET);
+        u64 valid;
+
+        /*
+         * Copy legacy XSAVE area, to avoid complications with CPUID
+         * leaves 0 and 1 in the loop below.
+         */
+        memcpy(xsave, src, XSAVE_HDR_OFFSET);
+
+        /* Set XSTATE_BV and possibly XCOMP_BV.  */
+        xsave->xsave_hdr.xstate_bv = xstate_bv;
+        if (cpu_has_xsaves)
+                xsave->xsave_hdr.xcomp_bv = host_xcr0 | XSTATE_COMPACTION_ENABLED;
+
+        /*
+         * Copy each region from the non-compacted offset to the
+         * possibly compacted offset.
+         */
+        valid = xstate_bv & ~XSTATE_FPSSE;
+        while (valid) {
+                u64 feature = valid & -valid;
+                int index = fls64(feature) - 1;
+                void *dest = get_xsave_addr(xsave, feature);
+
+                if (dest) {
+                        u32 size, offset, ecx, edx;
+                        cpuid_count(XSTATE_CPUID, index,
+                                    &size, &offset, &ecx, &edx);
+                        memcpy(dest, src + offset, size);
+                } else
+                        WARN_ON_ONCE(1);
+
+                valid -= feature;
+        }
+}
+
 static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu,
                                          struct kvm_xsave *guest_xsave)
 {
         if (cpu_has_xsave) {
-                memcpy(guest_xsave->region,
-                        &vcpu->arch.guest_fpu.state->xsave,
-                        vcpu->arch.guest_xstate_size);
-                *(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)] &=
-                        vcpu->arch.guest_supported_xcr0 | XSTATE_FPSSE;
+                memset(guest_xsave, 0, sizeof(struct kvm_xsave));
+                fill_xsave((u8 *) guest_xsave->region, vcpu);
         } else {
                 memcpy(guest_xsave->region,
                         &vcpu->arch.guest_fpu.state->fxsave,
@@ -3164,8 +3238,7 @@ static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu,
                  */
                 if (xstate_bv & ~kvm_supported_xcr0())
                         return -EINVAL;
-                memcpy(&vcpu->arch.guest_fpu.state->xsave,
-                        guest_xsave->region, vcpu->arch.guest_xstate_size);
+                load_xsave(vcpu, (u8 *)guest_xsave->region);
         } else {
                 if (xstate_bv & ~XSTATE_FPSSE)
                         return -EINVAL;
@@ -6882,6 +6955,9 @@ int fx_init(struct kvm_vcpu *vcpu)
                 return err;
 
         fpu_finit(&vcpu->arch.guest_fpu);
+        if (cpu_has_xsaves)
+                vcpu->arch.guest_fpu.state->xsave.xsave_hdr.xcomp_bv =
+                        host_xcr0 | XSTATE_COMPACTION_ENABLED;
 
         /*
          * Ensure guest xcr0 is valid for loading