From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Mon, 25 Sep 2017 17:19:01 +0000 (+0100)
Subject: x86/pv: Fix assertion failure in pv_emulate_privileged_op()
X-Git-Tag: 4.10.0-rc1~241^2~3
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=8a4b37c38c4be14a21556455fba9a0be5c0fe36b;p=people%2Fdariof%2Fxen.git

x86/pv: Fix assertion failure in pv_emulate_privileged_op()

The ABI of {read,write}_msr() requires them to use x86_emul_hw_exception() if
they report an exception with the emulator core.

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

diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c
index ef13d992f0..dd90713acf 100644
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -844,7 +844,12 @@ static int read_msr(unsigned int reg, uint64_t *val,
     int ret;
 
     if ( (ret = guest_rdmsr(curr, reg, val)) != X86EMUL_UNHANDLEABLE )
+    {
+        if ( ret == X86EMUL_EXCEPTION )
+            x86_emul_hw_exception(TRAP_gp_fault, 0, ctxt);
+
         return ret;
+    }
 
     switch ( reg )
     {
@@ -993,7 +998,12 @@ static int write_msr(unsigned int reg, uint64_t val,
     int ret;
 
     if ( (ret = guest_wrmsr(curr, reg, val)) != X86EMUL_UNHANDLEABLE )
+    {
+        if ( ret == X86EMUL_EXCEPTION )
+            x86_emul_hw_exception(TRAP_gp_fault, 0, ctxt);
+
         return ret;
+    }
 
     switch ( reg )
     {