diff options
| author | Ankur Arora <ankur.a.arora@oracle.com> | 2017-06-02 17:06:02 -0700 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2017-06-13 16:10:58 +0200 |
| commit | ae039001054b34c4a624539b32a8b6ff3403aaf9 (patch) | |
| tree | 593737839f22262a0c46b39d86987d741f1df8d7 /arch/x86/xen/smp.c | |
| parent | c9b5d98b25161a7ebee6ea59d6424dd9f33c1b99 (diff) | |
xen/vcpu: Handle xen_vcpu_setup() failure at boot
On PVH, PVHVM, at failure in the VCPUOP_register_vcpu_info hypercall
we limit the number of cpus to to MAX_VIRT_CPUS. However, if this
failure had occurred for a cpu beyond MAX_VIRT_CPUS, we continue
to function with > MAX_VIRT_CPUS.
This leads to problems at the next save/restore cycle when there
are > MAX_VIRT_CPUS threads going into stop_machine() but coming
back up there's valid state for only the first MAX_VIRT_CPUS.
This patch pulls the excess CPUs down via cpu_down().
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'arch/x86/xen/smp.c')
| -rw-r--r-- | arch/x86/xen/smp.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 82ac611f2fc1..e7f02eb73727 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -1,4 +1,5 @@ #include <linux/smp.h> +#include <linux/cpu.h> #include <linux/slab.h> #include <linux/cpumask.h> #include <linux/percpu.h> @@ -114,6 +115,36 @@ int xen_smp_intr_init(unsigned int cpu) return rc; } +void __init xen_smp_cpus_done(unsigned int max_cpus) +{ + int cpu, rc, count = 0; + + if (xen_hvm_domain()) + native_smp_cpus_done(max_cpus); + + if (xen_have_vcpu_info_placement) + return; + + for_each_online_cpu(cpu) { + if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) + continue; + + rc = cpu_down(cpu); + + if (rc == 0) { + /* + * Reset vcpu_info so this cpu cannot be onlined again. + */ + xen_vcpu_info_reset(cpu); + count++; + } else { + pr_warn("%s: failed to bring CPU %d down, error %d\n", + __func__, cpu, rc); + } + } + WARN(count, "%s: brought %d CPUs offline\n", __func__, count); +} + void xen_smp_send_reschedule(int cpu) { xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR); |