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| author | Ankur Arora <ankur.a.arora@oracle.com> | 2017-06-02 17:05:59 -0700 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2017-06-13 16:05:17 +0200 |
| commit | 0b64ffb8db4e310f77a01079ca752d946a8526b5 (patch) | |
| tree | 0975f7c4353148b0526752e84462945af44e7802 /arch/x86/xen/smp_hvm.c | |
| parent | ad73fd595c2ab168fdd01a266cbe6e4df95f8db0 (diff) | |
| download | linux-0b64ffb8db4e310f77a01079ca752d946a8526b5.tar.bz2 | |
xen/pvh*: Support > 32 VCPUs at domain restore
When Xen restores a PVHVM or PVH guest, its shared_info only holds
up to 32 CPUs. The hypercall VCPUOP_register_vcpu_info allows
us to setup per-page areas for VCPUs. This means we can boot
PVH* guests with more than 32 VCPUs. During restore the per-cpu
structure is allocated freshly by the hypervisor (vcpu_info_mfn is
set to INVALID_MFN) so that the newly restored guest can make a
VCPUOP_register_vcpu_info hypercall.
However, we end up triggering this condition in Xen:
/* Run this command on yourself or on other offline VCPUS. */
if ( (v != current) && !test_bit(_VPF_down, &v->pause_flags) )
which means we are unable to setup the per-cpu VCPU structures
for running VCPUS. The Linux PV code paths makes this work by
iterating over cpu_possible in xen_vcpu_restore() with:
1) is target CPU up (VCPUOP_is_up hypercall?)
2) if yes, then VCPUOP_down to pause it
3) VCPUOP_register_vcpu_info
4) if it was down, then VCPUOP_up to bring it back up
With Xen commit 192df6f9122d ("xen/x86: allow HVM guests to use
hypercalls to bring up vCPUs") this is available for non-PV guests.
As such first check if VCPUOP_is_up is actually possible before
trying this dance.
As most of this dance code is done already in xen_vcpu_restore()
let's make it callable on PV, PVH and PVHVM.
Based-on-patch-by: Konrad Wilk <konrad.wilk@oracle.com>
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_hvm.c')
| -rw-r--r-- | arch/x86/xen/smp_hvm.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/xen/smp_hvm.c b/arch/x86/xen/smp_hvm.c index 9e0fb9a015d4..6c8a805819ff 100644 --- a/arch/x86/xen/smp_hvm.c +++ b/arch/x86/xen/smp_hvm.c @@ -28,10 +28,20 @@ static void __init xen_hvm_smp_prepare_boot_cpu(void) static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus) { + int cpu; + native_smp_prepare_cpus(max_cpus); WARN_ON(xen_smp_intr_init(0)); xen_init_lock_cpu(0); + + for_each_possible_cpu(cpu) { + if (cpu == 0) + continue; + + /* Set default vcpu_id to make sure that we don't use cpu-0's */ + per_cpu(xen_vcpu_id, cpu) = XEN_VCPU_ID_INVALID; + } } #ifdef CONFIG_HOTPLUG_CPU |