Commit d128e2ae authored by Juergen Gross's avatar Juergen Gross Committed by Zheng Zengkai
Browse files

x86/xen: fix percpu vcpu_info allocation 

stable inclusion
from stable-v6.6.5
commit 602aa0efcf0dba24ef7bd78be9262285b33b4614
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8N21P

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=602aa0efcf0dba24ef7bd78be9262285b33b4614



--------------------------------

[ Upstream commit db2832309a82b9acc4b8cc33a1831d36507ec13e ]

Today the percpu struct vcpu_info is allocated via DEFINE_PER_CPU(),
meaning that it could cross a page boundary. In this case registering
it with the hypervisor will fail, resulting in a panic().

This can easily be fixed by using DEFINE_PER_CPU_ALIGNED() instead,
as struct vcpu_info is guaranteed to have a size of 64 bytes, matching
the cache line size of x86 64-bit processors (Xen doesn't support
32-bit processors).

Fixes: 5ead97c8 ("xen: Core Xen implementation")
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.con>
Link: https://lore.kernel.org/r/20231124074852.25161-1-jgross@suse.com


Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent d88cc962

arch/x86/xen/enlighten.c

+5 −1
Original line number Original line Diff line number Diff line
@@ -33,9 +33,12 @@ EXPORT_SYMBOL_GPL(hypercall_page); 
 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info

 * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info

 * but during boot it is switched to point to xen_vcpu_info.

 * but during boot it is switched to point to xen_vcpu_info.

 * The pointer is used in xen_evtchn_do_upcall to acknowledge pending events.

 * The pointer is used in xen_evtchn_do_upcall to acknowledge pending events.

 * Make sure that xen_vcpu_info doesn't cross a page boundary by making it

 * cache-line aligned (the struct is guaranteed to have a size of 64 bytes,

 * which matches the cache line size of 64-bit x86 processors).

 */

 */

DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);

DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);

DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);

DEFINE_PER_CPU_ALIGNED(struct vcpu_info, xen_vcpu_info);





/* Linux <-> Xen vCPU id mapping */

/* Linux <-> Xen vCPU id mapping */

DEFINE_PER_CPU(uint32_t, xen_vcpu_id);

DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
@@ -160,6 +163,7 @@ void xen_vcpu_setup(int cpu) 
	int err;

	int err;

	struct vcpu_info *vcpup;

	struct vcpu_info *vcpup;





	BUILD_BUG_ON(sizeof(*vcpup) > SMP_CACHE_BYTES);

	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);

	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);





	/*

	/*

arch/x86/xen/xen-ops.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -21,7 +21,7 @@ extern void *xen_initial_gdt; 
struct trap_info;

struct trap_info;

void xen_copy_trap_info(struct trap_info *traps);

void xen_copy_trap_info(struct trap_info *traps);





DECLARE_PER_CPU(struct vcpu_info, xen_vcpu_info);

DECLARE_PER_CPU_ALIGNED(struct vcpu_info, xen_vcpu_info);

DECLARE_PER_CPU(unsigned long, xen_cr3);

DECLARE_PER_CPU(unsigned long, xen_cr3);

DECLARE_PER_CPU(unsigned long, xen_current_cr3);

DECLARE_PER_CPU(unsigned long, xen_current_cr3);