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List: xen-cvs
Subject: [xen stable-4.16] x86/pv-shim: correct ballooning up for compat guests
From: patchbot () xen ! org
Date: 2022-10-31 22:13:03
Message-ID: E1opd1j-0000Cd-DA () xenbits ! xenproject ! org
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commit 2f75e3654f00a62bd1f446a7424ccd56750a2e15
Author: Igor Druzhinin <igor.druzhinin@citrix.com>
AuthorDate: Mon Oct 31 13:28:15 2022 +0100
Commit: Jan Beulich <jbeulich@suse.com>
CommitDate: Mon Oct 31 13:28:15 2022 +0100
x86/pv-shim: correct ballooning up for compat guests
The compat layer for multi-extent memory ops may need to split incoming
requests. Since the guest handles in the interface structures may not be
altered, it does so by leveraging do_memory_op()'s continuation
handling: It hands on non-initial requests with a non-zero start extent,
with the (native) handle suitably adjusted down. As a result
do_memory_op() sees only the first of potentially several requests with
start extent being zero. It's only that case when the function would
issue a call to pv_shim_online_memory(), yet the range then covers only
the first sub-range that results from the split.
Address that breakage by making a complementary call to
pv_shim_online_memory() in compat layer.
Fixes: b2245acc60c3 ("xen/pvshim: memory hotplug")
Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: a0bfdd201ea12aa5679bb8944d63a4e0d3c23160
master date: 2022-10-28 15:48:50 +0200
---
xen/common/compat/memory.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/xen/common/compat/memory.c b/xen/common/compat/memory.c
index c43fa97cf1..a0e0562a40 100644
--- a/xen/common/compat/memory.c
+++ b/xen/common/compat/memory.c
@@ -7,6 +7,7 @@ EMIT_FILE;
#include <xen/event.h>
#include <xen/mem_access.h>
#include <asm/current.h>
+#include <asm/guest.h>
#include <compat/memory.h>
#define xen_domid_t domid_t
@@ -146,7 +147,10 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat)
nat.rsrv->nr_extents = end_extent;
++split;
}
-
+ /* Avoid calling pv_shim_online_memory() when in a continuation. */
+ if ( pv_shim && op != XENMEM_decrease_reservation && !start_extent )
+ pv_shim_online_memory(cmp.rsrv.nr_extents - nat.rsrv->nr_extents,
+ cmp.rsrv.extent_order);
break;
case XENMEM_exchange:
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.16
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