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authorAnkur Arora <ankur.a.arora@oracle.com>2017-06-03 03:05:59 +0300
committerJuergen Gross <jgross@suse.com>2017-06-13 17:05:17 +0300
commit0b64ffb8db4e310f77a01079ca752d946a8526b5 (patch)
tree0975f7c4353148b0526752e84462945af44e7802 /include/xen
parentad73fd595c2ab168fdd01a266cbe6e4df95f8db0 (diff)
downloadlinux-0b64ffb8db4e310f77a01079ca752d946a8526b5.tar.xz
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 'include/xen')
-rw-r--r--include/xen/xen-ops.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index c44a2ee8c8f8..218e6aae5433 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -15,6 +15,8 @@ static inline uint32_t xen_vcpu_nr(int cpu)
return per_cpu(xen_vcpu_id, cpu);
}
+#define XEN_VCPU_ID_INVALID U32_MAX
+
void xen_arch_pre_suspend(void);
void xen_arch_post_suspend(int suspend_cancelled);