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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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0b64ffb8db
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>
75 lines
1.6 KiB
C
75 lines
1.6 KiB
C
#include <asm/smp.h>
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#include <xen/events.h>
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#include "xen-ops.h"
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#include "smp.h"
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static void __init xen_hvm_smp_prepare_boot_cpu(void)
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{
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BUG_ON(smp_processor_id() != 0);
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native_smp_prepare_boot_cpu();
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/*
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* Setup vcpu_info for boot CPU. Secondary CPUs get their vcpu_info
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* in xen_cpu_up_prepare_hvm().
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*/
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xen_vcpu_setup(0);
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/*
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* The alternative logic (which patches the unlock/lock) runs before
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* the smp bootup up code is activated. Hence we need to set this up
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* the core kernel is being patched. Otherwise we will have only
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* modules patched but not core code.
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*/
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xen_init_spinlocks();
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}
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static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus)
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{
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int cpu;
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native_smp_prepare_cpus(max_cpus);
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WARN_ON(xen_smp_intr_init(0));
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xen_init_lock_cpu(0);
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for_each_possible_cpu(cpu) {
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if (cpu == 0)
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continue;
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/* Set default vcpu_id to make sure that we don't use cpu-0's */
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per_cpu(xen_vcpu_id, cpu) = XEN_VCPU_ID_INVALID;
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}
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}
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#ifdef CONFIG_HOTPLUG_CPU
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static void xen_hvm_cpu_die(unsigned int cpu)
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{
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if (common_cpu_die(cpu) == 0) {
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xen_smp_intr_free(cpu);
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xen_uninit_lock_cpu(cpu);
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xen_teardown_timer(cpu);
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}
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}
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#else
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static void xen_hvm_cpu_die(unsigned int cpu)
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{
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BUG();
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}
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#endif
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void __init xen_hvm_smp_init(void)
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{
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if (!xen_have_vector_callback)
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return;
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smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus;
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smp_ops.smp_send_reschedule = xen_smp_send_reschedule;
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smp_ops.cpu_die = xen_hvm_cpu_die;
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smp_ops.send_call_func_ipi = xen_smp_send_call_function_ipi;
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smp_ops.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi;
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smp_ops.smp_prepare_boot_cpu = xen_hvm_smp_prepare_boot_cpu;
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}
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