arm/xen: fix xen_vcpu_info allocation alignment

xen_vcpu_info is a percpu area than needs to be mapped by Xen.
Currently, it could cross a page boundary resulting in Xen being unable
to map it:

[    0.567318] kernel BUG at arch/arm64/xen/../../arm/xen/enlighten.c:164!
[    0.574002] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP

Fix the issue by using __alloc_percpu and requesting alignment for the
memory allocation.

Signed-off-by: Stefano Stabellini <stefano.stabellini@amd.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.22.394.2311221501340.2053963@ubuntu-linux-20-04-desktop
Fixes: 24d5373dda7c ("arm/xen: Use alloc_percpu rather than __alloc_percpu")
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 9afdc4c4a5dc15f9bf4a1972894e2b046f5489d6..a395b6c0aae2a92e40b88dc37faa2829df9f95f0 100644 (file)
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -484,7 +484,8 @@ static int __init xen_guest_init(void)
         * for secondary CPUs as they are brought up.
         * For uniformity we use VCPUOP_register_vcpu_info even on cpu0.
         */
-       xen_vcpu_info = alloc_percpu(struct vcpu_info);
+       xen_vcpu_info = __alloc_percpu(sizeof(struct vcpu_info),
+                                      1 << fls(sizeof(struct vcpu_info) - 1));
        if (xen_vcpu_info == NULL)
                return -ENOMEM;