This is a global variable (actually 3, one per GUEST_PAGING_LEVEL), operated
on using atomics only (with no regard to what else shares the same cacheline),
which emits a diagnostic (in debug builds only) without changing any program
behaviour.
Based on read-only p2m types including logdirty, this diagnostic can be
tripped by entirely legitimate guest behaviour.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Roger Pau Monné <roger....@citrix.com>
CC: Wei Liu <w...@xen.org>
CC: George Dunlap <george.dun...@eu.citrix.com>
CC: Tim Deegan <t...@xen.org>
---
xen/arch/x86/mm/shadow/multi.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
index 8b3e678fa0fa..3b06cfaf9a5a 100644
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -2597,14 +2597,7 @@ static int cf_check sh_page_fault(
/* Ignore attempts to write to read-only memory. */
if ( p2m_is_readonly(p2mt) && (ft == ft_demand_write) )
- {
- static unsigned long lastpage;
- if ( xchg(&lastpage, va & PAGE_MASK) != (va & PAGE_MASK) )
- gdprintk(XENLOG_DEBUG, "guest attempted write to read-only memory"
- " page. va page=%#lx, mfn=%#lx\n",
- va & PAGE_MASK, mfn_x(gmfn));
goto emulate_readonly; /* skip over the instruction */
- }
/* In HVM guests, we force CR0.WP always to be set, so that the
* pagetables are always write-protected. If the guest thinks
--
2.11.0
