tmakin/ack-tegra
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

x86/xen: fix xen_hypercall_hvm() to not clobber %rbx

Browse Source 
[ Upstream commit 98a5cfd2320966f40fe049a9855f8787f0126825 ]

xen_hypercall_hvm(), which is used when running as a Xen PVH guest at
most only once during early boot, is clobbering %rbx. Depending on
whether the caller relies on %rbx to be preserved across the call or
not, this clobbering might result in an early crash of the system.

This can be avoided by using an already saved register instead of %rbx.

Fixes: b4845bb63838 ("x86/xen: add central hypercall functions")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Juergen Gross
2025-02-05 09:43:31 +01:00
committed by Greg Kroah-Hartman
parent f014a926eb
commit 4890a0858c
1 changed files with 2 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/x86/xen/xen-head.S
+2 -2
View File
@@ -117,8 +117,8 @@ SYM_FUNC_START(xen_hypercall_hvm)
pop %ebx
pop %eax
#else
lea xen_hypercall_amd(%rip), %rbx
cmp %rax, %rbx
lea xen_hypercall_amd(%rip), %rcx
cmp %rax, %rcx
#ifdef CONFIG_FRAME_POINTER
pop %rax /* Dummy pop. */
#endif