[PATCH linux v3 0/9] xen: pvhvm: support bootup on secondary vCPUs

From: Vitaly Kuznetsov
Date: Tue Jul 26 2016 - 08:30:40 EST


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 we
need to have a mapping between Linux's and Xen's vCPU ids.

This series solves the issue for x86 PVHVM guests. PV guests don't (and
probably won't) support kdump so I always assume Xen's vCPU id == Linux's
vCPU id. ARM guests will probably need to get proper mapping once we start
supporting kexec/kdump there.

Changes since v2:
- Use 'uint32_t' for xen_vcpu_id mapping [Julien Grall]
- Rebased to linux-4.7

Changes since v1:
- "x86/acpi: store ACPI ids from MADT for future usage" patch added.
- Use ACPI ids instead of vLAPIC ids/2 [Andrew Cooper, Jan Beulich]
- Introduce xen_vcpu_nr() helper [David Vrabel].
- Modify all callers of HYPERVISOR_vcpu_op() instead of modifying
HYPERVISOR_vcpu_op() [David Vrabel]

Vitaly Kuznetsov (9):
x86/xen: update cpuid.h from Xen-4.7
x86/acpi: store ACPI ids from MADT for future usage
xen: introduce xen_vcpu_id mapping
x86/xen: use xen_vcpu_id mapping for HYPERVISOR_vcpu_op
x86/xen: use xen_vcpu_id mapping when pointing vcpu_info to the
shared_info page
xen/events: use xen_vcpu_id mapping in events_base
xen/events: fifo: use xen_vcpu_id mapping
xen/evtchn: use xen_vcpu_id mapping
xen/pvhvm: run xen_vcpu_setup() for the boot CPU

arch/arm/xen/enlighten.c | 13 +++++++++++-
arch/x86/include/asm/cpu.h | 1 +
arch/x86/include/asm/smp.h | 2 ++
arch/x86/include/asm/xen/cpuid.h | 5 ++++-
arch/x86/kernel/acpi/boot.c | 16 ++++++++++----
arch/x86/kernel/apic/apic.c | 2 ++
arch/x86/kernel/setup_percpu.c | 3 +++
arch/x86/xen/enlighten.c | 45 +++++++++++++++++++++++++++++++---------
arch/x86/xen/irq.c | 3 ++-
arch/x86/xen/smp.c | 18 +++++++++++-----
arch/x86/xen/time.c | 18 ++++++++++------
arch/x86/xen/xen-ops.h | 1 +
drivers/xen/events/events_base.c | 13 ++++++------
drivers/xen/events/events_fifo.c | 2 +-
drivers/xen/evtchn.c | 3 ++-
drivers/xen/time.c | 2 +-
include/xen/xen-ops.h | 6 ++++++
17 files changed, 116 insertions(+), 37 deletions(-)

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2.7.4