From: Jan Beulich <jbeulich@suse.com>
Date: Fri, 15 Jun 2018 09:49:06 +0000 (+0200)
Subject: x86/HVM: account for fully eager FPU mode in emulation
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~62
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=e23d2234e08872ac1c719f3e338994581483440f;p=xen.git

x86/HVM: account for fully eager FPU mode in emulation

In fully eager mode we must not clear fpu_dirtied, set CR0.TS, or invoke
the fpu_leave() hook. Instead do what the mode's name says: Restore
state right away.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Release-acked-by: Juergen Gross <jgross@suse.com>
---

diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index c9aa18884d..03a4944e88 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -2139,13 +2139,20 @@ static void hvmemul_put_fpu(
     if ( backout == X86EMUL_FPU_fpu )
     {
         /*
-         * To back out changes to the register file simply adjust state such
-         * that upon next FPU insn use by the guest we'll reload the state
-         * saved (or freshly loaded) by hvmemul_get_fpu().
+         * To back out changes to the register file
+         * - in fully eager mode, restore original state immediately,
+         * - in lazy mode, simply adjust state such that upon next FPU insn
+         *   use by the guest we'll reload the state saved (or freshly loaded)
+         *   by hvmemul_get_fpu().
          */
-        curr->fpu_dirtied = false;
-        stts();
-        hvm_funcs.fpu_leave(curr);
+        if ( curr->arch.fully_eager_fpu )
+            vcpu_restore_fpu_eager(curr);
+        else
+        {
+            curr->fpu_dirtied = false;
+            stts();
+            hvm_funcs.fpu_leave(curr);
+        }
     }
 }