From: Jan Beulich <jbeulich@suse.com>
Date: Thu, 15 Nov 2018 15:43:03 +0000 (+0100)
Subject: x86/HVM: hvm_map_guest_frame_rw() should respect p2m_ioreq_server
X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~2917
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=1f04469a0793fb9500d51215ee935849ec74ed56;p=xen.git

x86/HVM: hvm_map_guest_frame_rw() should respect p2m_ioreq_server

Writes to such pages would need to be handed to the emulator, which we're
not prepared to do at this point.

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

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 65ab6a9b23..0bc676cd94 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -2558,7 +2558,8 @@ static void *_hvm_map_guest_frame(unsigned long gfn, bool_t permanent,
 
     if ( writable )
     {
-        if ( unlikely(p2m_is_discard_write(p2mt)) )
+        if ( unlikely(p2m_is_discard_write(p2mt)) ||
+             unlikely(p2mt == p2m_ioreq_server) )
             *writable = 0;
         else if ( !permanent )
             paging_mark_pfn_dirty(d, _pfn(gfn));