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| author | Juergen Gross <jgross@suse.com> | 2023-11-24 08:48:52 +0100 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2023-11-28 12:47:11 +0100 |
| commit | db2832309a82b9acc4b8cc33a1831d36507ec13e (patch) | |
| tree | 372b03193c3333e5cef2b001c67adcca0944c189 | |
| parent | 7bf9a6b46549852a37e6d07e52c601c3c706b562 (diff) | |
| download | linux-db2832309a82b9acc4b8cc33a1831d36507ec13e.tar.gz | |
x86/xen: fix percpu vcpu_info allocation
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: 5ead97c84fa7 ("xen: Core Xen implementation")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.con>
Link: https://lore.kernel.org/r/20231124074852.25161-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
| -rw-r--r-- | arch/x86/xen/enlighten.c | 6 | ||||
| -rw-r--r-- | arch/x86/xen/xen-ops.h | 2 |
2 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 0337392a312141..3c61bb98c10e28 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -33,9 +33,12 @@ EXPORT_SYMBOL_GPL(hypercall_page); * 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. * 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_info); +DEFINE_PER_CPU_ALIGNED(struct vcpu_info, xen_vcpu_info); /* Linux <-> Xen vCPU id mapping */ DEFINE_PER_CPU(uint32_t, xen_vcpu_id); @@ -160,6 +163,7 @@ void xen_vcpu_setup(int cpu) int err; struct vcpu_info *vcpup; + BUILD_BUG_ON(sizeof(*vcpup) > SMP_CACHE_BYTES); BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info); /* diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h index 408a2aa66c6922..a87ab36889e76c 100644 --- a/arch/x86/xen/xen-ops.h +++ b/arch/x86/xen/xen-ops.h @@ -21,7 +21,7 @@ extern void *xen_initial_gdt; struct trap_info; 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_current_cr3); |