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authorEdgar E. Iglesias <edgar.iglesias@amd.com>2024-08-08 13:30:12 +0200
committerEdgar E. Iglesias <edgar.iglesias@amd.com>2024-09-04 16:50:42 +0200
commitb421a0dce68263f93fca961a742873003af7c681 (patch)
tree6ac83c58dfb263e475609db21d02b43b7fbb7da4
parent4850c6cc56201552e6162eb24ebd91c6dffeb19c (diff)
hw/arm: xenpvh: Add support for SMP guests
Add SMP support for Xen PVH ARM guests. Create ms->smp.max_cpus ioreq servers to handle hotplug. Note that ms->smp.max_cpus will be passed to us by the user (Xen tools) set to the guests maxvcpus. The value in mc->max_cpus is an absolute maximum for the -smp option and won't be used to setup ioreq servers unless the user explicitly specifies it with -smp. If the user doesn't pass -smp on the command-line, smp.cpus and smp.max_cpus will default to 1. Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
-rw-r--r--hw/arm/xen_arm.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/hw/arm/xen_arm.c b/hw/arm/xen_arm.c
index 5f75cc3779..fda65d0d8d 100644
--- a/hw/arm/xen_arm.c
+++ b/hw/arm/xen_arm.c
@@ -173,7 +173,7 @@ static void xen_arm_init(MachineState *machine)
xen_init_ram(machine);
- xen_register_ioreq(xam->state, machine->smp.cpus, &xen_memory_listener);
+ xen_register_ioreq(xam->state, machine->smp.max_cpus, &xen_memory_listener);
xen_create_virtio_mmio_devices(xam);
@@ -218,7 +218,26 @@ static void xen_arm_machine_class_init(ObjectClass *oc, void *data)
MachineClass *mc = MACHINE_CLASS(oc);
mc->desc = "Xen PVH ARM machine";
mc->init = xen_arm_init;
- mc->max_cpus = 1;
+
+ /*
+ * mc->max_cpus holds the MAX value allowed in the -smp command-line opts.
+ *
+ * 1. If users don't pass any -smp option:
+ * ms->smp.cpus will default to 1.
+ * ms->smp.max_cpus will default to 1.
+ *
+ * 2. If users pass -smp X:
+ * ms->smp.cpus will be set to X.
+ * ms->smp.max_cpus will also be set to X.
+ *
+ * 3. If users pass -smp X,maxcpus=Y:
+ * ms->smp.cpus will be set to X.
+ * ms->smp.max_cpus will be set to Y.
+ *
+ * In scenarios 2 and 3, if X or Y are set to something larger than
+ * mc->max_cpus, QEMU will bail out with an error message.
+ */
+ mc->max_cpus = GUEST_MAX_VCPUS;
mc->default_machine_opts = "accel=xen";
/* Set explicitly here to make sure that real ram_size is passed */
mc->default_ram_size = 0;