From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Xen-devel <xen-devel@lists.xen.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Jan Beulich <JBeulich@suse.com>
Subject: [PATCH 3/6] x86/domctl: Simplfy XEN_DOMCTL_getvcpuextstate when xsave is not in use
Date: Mon, 12 Sep 2016 10:51:37 +0100 [thread overview]
Message-ID: <1473673900-8585-4-git-send-email-andrew.cooper3@citrix.com> (raw)
In-Reply-To: <1473673900-8585-1-git-send-email-andrew.cooper3@citrix.com>
Older guests will not use xsave even if it is available. As such, their
xcr0_accum will be 0 at the point of migrate.
If it is empty, forgo the memory allocation and serialisation into a
zero-length buffer.
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
---
xen/arch/x86/domctl.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 815bd33..5aa9f3a 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -1087,11 +1087,13 @@ long arch_do_domctl(
ret = -EFAULT;
offset += sizeof(v->arch.xcr0_accum);
- if ( !ret )
+
+ /* Serialise xsave state, if there is any. */
+ if ( !ret && size > PV_XSAVE_HDR_SIZE )
{
- void *xsave_area;
+ unsigned int xsave_size = size - PV_XSAVE_HDR_SIZE;
+ void *xsave_area = xmalloc_bytes(xsave_size);
- xsave_area = xmalloc_bytes(size);
if ( !xsave_area )
{
ret = -ENOMEM;
@@ -1099,11 +1101,10 @@ long arch_do_domctl(
goto vcpuextstate_out;
}
- expand_xsave_states(v, xsave_area,
- size - PV_XSAVE_HDR_SIZE);
+ expand_xsave_states(v, xsave_area, xsave_size);
if ( copy_to_guest_offset(evc->buffer, offset, xsave_area,
- size - PV_XSAVE_HDR_SIZE) )
+ xsave_size) )
ret = -EFAULT;
xfree(xsave_area);
}
--
2.1.4
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next prev parent reply other threads:[~2016-09-12 9:51 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-12 9:51 [PATCH 0/6] Fix multiple issues with xsave state handling on migrate Andrew Cooper
2016-09-12 9:51 ` [PATCH 1/6] x86/domctl: Introduce PV_XSAVE_HDR_SIZE and remove its opencoding Andrew Cooper
2016-09-12 11:05 ` Jan Beulich
2016-09-12 9:51 ` [PATCH 2/6] x86/domctl: Fix TOCTOU race with the use of XEN_DOMCTL_getvcpuextstate Andrew Cooper
2016-09-12 11:17 ` Jan Beulich
2016-09-12 12:02 ` Andrew Cooper
2016-09-12 12:33 ` Jan Beulich
2016-09-12 13:09 ` Andrew Cooper
2016-09-12 13:35 ` Jan Beulich
2016-09-12 13:37 ` Jan Beulich
2016-09-12 9:51 ` Andrew Cooper [this message]
2016-09-12 11:26 ` [PATCH 3/6] x86/domctl: Simplfy XEN_DOMCTL_getvcpuextstate when xsave is not in use Jan Beulich
2016-09-12 9:51 ` [PATCH 4/6] x86/xstate: Fix latent bugs in expand_xsave_states() Andrew Cooper
2016-09-12 11:41 ` Jan Beulich
2016-09-12 12:29 ` Andrew Cooper
2016-09-12 12:41 ` Jan Beulich
2016-09-12 12:43 ` Jan Beulich
2016-09-12 13:57 ` Andrew Cooper
2016-09-12 14:13 ` Jan Beulich
2016-09-12 9:51 ` [PATCH 5/6] x86/domctl: Fix migration of guests which are not using xsave Andrew Cooper
2016-09-12 12:14 ` Jan Beulich
2016-09-12 12:46 ` Andrew Cooper
2016-09-12 13:41 ` Jan Beulich
2016-09-12 9:51 ` [PATCH 6/6] x86/xstate: Fix latent bugs in compress_xsave_states() Andrew Cooper
2016-09-12 12:27 ` Jan Beulich
2016-09-12 12:59 ` Andrew Cooper
2016-09-12 13:47 ` Jan Beulich
2016-09-12 15:28 ` Andrew Cooper
2016-09-12 16:10 ` Jan Beulich
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