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| author | Vitaly Kuznetsov <vkuznets@redhat.com> | 2016-06-30 17:56:37 +0200 |
|---|---|---|
| committer | David Vrabel <david.vrabel@citrix.com> | 2016-07-25 13:31:16 +0100 |
| commit | 88e957d6e47f1232ad15b21e54a44f1147ea8c1b (patch) | |
| tree | e7384643d570bd17463455d26fc63ada4ecf24a4 /arch/arm | |
| parent | 3e9e57fad3d8530aa30787f861c710f598ddc4e7 (diff) | |
| download | linux-88e957d6e47f1232ad15b21e54a44f1147ea8c1b.tar.bz2 | |
xen: introduce xen_vcpu_id mapping
It may happen that Xen's and Linux's ideas of vCPU id diverge. In
particular, when we crash on a secondary vCPU we may want to do kdump
and unlike plain kexec where we do migrate_to_reboot_cpu() we try
booting on the vCPU which crashed. This doesn't work very well for
PVHVM guests as we have a number of hypercalls where we pass vCPU id
as a parameter. These hypercalls either fail or do something
unexpected.
To solve the issue introduce percpu xen_vcpu_id mapping. ARM and PV
guests get direct mapping for now. Boot CPU for PVHVM guest gets its
id from CPUID. With secondary CPUs it is a bit more
trickier. Currently, we initialize IPI vectors before these CPUs boot
so we can't use CPUID. Use ACPI ids from MADT instead.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/xen/enlighten.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c index 2f4c3aa540eb..72cf06bf43f2 100644 --- a/arch/arm/xen/enlighten.c +++ b/arch/arm/xen/enlighten.c @@ -49,6 +49,10 @@ struct shared_info *HYPERVISOR_shared_info = (void *)&xen_dummy_shared_info; DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); static struct vcpu_info __percpu *xen_vcpu_info; +/* Linux <-> Xen vCPU id mapping */ +DEFINE_PER_CPU(int, xen_vcpu_id) = -1; +EXPORT_PER_CPU_SYMBOL(xen_vcpu_id); + /* These are unused until we support booting "pre-ballooned" */ unsigned long xen_released_pages; struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; @@ -167,6 +171,9 @@ static void xen_percpu_init(void) pr_info("Xen: initializing cpu%d\n", cpu); vcpup = per_cpu_ptr(xen_vcpu_info, cpu); + /* Direct vCPU id mapping for ARM guests. */ + per_cpu(xen_vcpu_id, cpu) = cpu; + info.mfn = virt_to_gfn(vcpup); info.offset = xen_offset_in_page(vcpup); @@ -388,6 +395,9 @@ static int __init xen_guest_init(void) if (xen_vcpu_info == NULL) return -ENOMEM; + /* Direct vCPU id mapping for ARM guests. */ + per_cpu(xen_vcpu_id, 0) = 0; + xen_auto_xlat_grant_frames.count = gnttab_max_grant_frames(); if (xen_xlate_map_ballooned_pages(&xen_auto_xlat_grant_frames.pfn, &xen_auto_xlat_grant_frames.vaddr, |