Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-10 06:01:57 +00:00
Code Issues Packages Projects Releases Wiki Activity

x86/cpu: fix unbootable VMs by inlining memcmp() in hypervisor_cpuid_base()

Browse Source 
If this memcmp() is not inlined then PVH early boot code can call
into KASAN-instrumented memcmp() which results in unbootable VMs:

	pvh_start_xen
	xen_prepare_pvh
	xen_cpuid_base
	hypervisor_cpuid_base
	memcmp

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Juergen Gross <jgross@suse.com>
Message-ID: <20240802154253.482658-2-adobriyan@gmail.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
This commit is contained in:
Alexey Dobriyan 2024-08-02 18:42:52 +03:00 committed by Juergen Gross
parent 661362e3dc
commit 416a33c9af
1 changed files with 6 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/x86/include/asm/cpuid.h
View File

@ -196,7 +196,12 @@ static inline uint32_t hypervisor_cpuid_base(const char *sig, uint32_t leaves)
for_each_possible_hypervisor_cpuid_base(base) {
cpuid(base, &eax, &signature[0], &signature[1], &signature[2]);
if (!memcmp(sig, signature, 12) &&
/*
* This must not compile to "call memcmp" because it's called
* from PVH early boot code before instrumentation is set up
* and memcmp() itself may be instrumented.
*/
if (!__builtin_memcmp(sig, signature, 12) &&
(leaves == 0 || ((eax - base) >= leaves)))
return base;
}