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-rw-r--r--target-i386/machine.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/target-i386/machine.c b/target-i386/machine.c
index 3659db9e94..f9ec581faa 100644
--- a/target-i386/machine.c
+++ b/target-i386/machine.c
@@ -252,6 +252,24 @@ static void cpu_pre_save(void *opaque)
}
env->fpregs_format_vmstate = 0;
+
+ /*
+ * Real mode guest segments register DPL should be zero.
+ * Older KVM version were setting it wrongly.
+ * Fixing it will allow live migration to host with unrestricted guest
+ * support (otherwise the migration will fail with invalid guest state
+ * error).
+ */
+ if (!(env->cr[0] & CR0_PE_MASK) &&
+ (env->segs[R_CS].flags >> DESC_DPL_SHIFT & 3) != 0) {
+ env->segs[R_CS].flags &= ~(env->segs[R_CS].flags & DESC_DPL_MASK);
+ env->segs[R_DS].flags &= ~(env->segs[R_DS].flags & DESC_DPL_MASK);
+ env->segs[R_ES].flags &= ~(env->segs[R_ES].flags & DESC_DPL_MASK);
+ env->segs[R_FS].flags &= ~(env->segs[R_FS].flags & DESC_DPL_MASK);
+ env->segs[R_GS].flags &= ~(env->segs[R_GS].flags & DESC_DPL_MASK);
+ env->segs[R_SS].flags &= ~(env->segs[R_SS].flags & DESC_DPL_MASK);
+ }
+
}
static int cpu_post_load(void *opaque, int version_id)
@@ -260,6 +278,24 @@ static int cpu_post_load(void *opaque, int version_id)
CPUX86State *env = &cpu->env;
int i;
+ /*
+ * Real mode guest segments register DPL should be zero.
+ * Older KVM version were setting it wrongly.
+ * Fixing it will allow live migration from such host that don't have
+ * restricted guest support to a host with unrestricted guest support
+ * (otherwise the migration will fail with invalid guest state
+ * error).
+ */
+ if (!(env->cr[0] & CR0_PE_MASK) &&
+ (env->segs[R_CS].flags >> DESC_DPL_SHIFT & 3) != 0) {
+ env->segs[R_CS].flags &= ~(env->segs[R_CS].flags & DESC_DPL_MASK);
+ env->segs[R_DS].flags &= ~(env->segs[R_DS].flags & DESC_DPL_MASK);
+ env->segs[R_ES].flags &= ~(env->segs[R_ES].flags & DESC_DPL_MASK);
+ env->segs[R_FS].flags &= ~(env->segs[R_FS].flags & DESC_DPL_MASK);
+ env->segs[R_GS].flags &= ~(env->segs[R_GS].flags & DESC_DPL_MASK);
+ env->segs[R_SS].flags &= ~(env->segs[R_SS].flags & DESC_DPL_MASK);
+ }
+
/* XXX: restore FPU round state */
env->fpstt = (env->fpus_vmstate >> 11) & 7;
env->fpus = env->fpus_vmstate & ~0x3800;