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[PULL 12/62] i386/xen: Implement SCHEDOP_poll and SCHEDOP_yield
From: |
Paolo Bonzini |
Subject: |
[PULL 12/62] i386/xen: Implement SCHEDOP_poll and SCHEDOP_yield |
Date: |
Thu, 2 Mar 2023 13:29:39 +0100 |
From: David Woodhouse <dwmw@amazon.co.uk>
They both do the same thing and just call sched_yield. This is enough to
stop the Linux guest panicking when running on a host kernel which doesn't
intercept SCHEDOP_poll and lets it reach userspace.
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Paul Durrant <paul@xen.org>
---
target/i386/kvm/xen-emu.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c
index 4ed833656f72..ebea27caf634 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -234,6 +234,19 @@ static bool kvm_xen_hcall_sched_op(struct kvm_xen_exit
*exit, X86CPU *cpu,
err = schedop_shutdown(cs, arg);
break;
+ case SCHEDOP_poll:
+ /*
+ * Linux will panic if this doesn't work. Just yield; it's not
+ * worth overthinking it because with event channel handling
+ * in KVM, the kernel will intercept this and it will never
+ * reach QEMU anyway. The semantics of the hypercall explicltly
+ * permit spurious wakeups.
+ */
+ case SCHEDOP_yield:
+ sched_yield();
+ err = 0;
+ break;
+
default:
return false;
}
--
2.39.1
- [PULL 03/62] xen: Add XEN_DISABLED mode and make it default, (continued)
- [PULL 03/62] xen: Add XEN_DISABLED mode and make it default, Paolo Bonzini, 2023/03/02
- [PULL 05/62] i386/kvm: handle Xen HVM cpuid leaves, Paolo Bonzini, 2023/03/02
- [PULL 04/62] i386/kvm: Add xen-version KVM accelerator property and init KVM Xen support, Paolo Bonzini, 2023/03/02
- [PULL 01/62] include: import Xen public headers to hw/xen/interface, Paolo Bonzini, 2023/03/02
- [PULL 06/62] i386/kvm: Set Xen vCPU ID in KVM, Paolo Bonzini, 2023/03/02
- [PULL 07/62] xen-platform: exclude vfio-pci from the PCI platform unplug, Paolo Bonzini, 2023/03/02
- [PULL 08/62] xen-platform: allow its creation with XEN_EMULATE mode, Paolo Bonzini, 2023/03/02
- [PULL 09/62] i386/xen: handle guest hypercalls, Paolo Bonzini, 2023/03/02
- [PULL 10/62] i386/xen: implement HYPERVISOR_xen_version, Paolo Bonzini, 2023/03/02
- [PULL 11/62] i386/xen: implement HYPERVISOR_sched_op, SCHEDOP_shutdown, Paolo Bonzini, 2023/03/02
- [PULL 12/62] i386/xen: Implement SCHEDOP_poll and SCHEDOP_yield,
Paolo Bonzini <=
- [PULL 13/62] hw/xen: Add xen_overlay device for emulating shared xenheap pages, Paolo Bonzini, 2023/03/02
- [PULL 15/62] i386/xen: add pc_machine_kvm_type to initialize XEN_EMULATE mode, Paolo Bonzini, 2023/03/02
- [PULL 14/62] xen: Permit --xen-domid argument when accel is KVM, Paolo Bonzini, 2023/03/02
- [PULL 16/62] i386/xen: manage and save/restore Xen guest long_mode setting, Paolo Bonzini, 2023/03/02
- [PULL 19/62] i386/xen: implement HYPERVISOR_hvm_op, Paolo Bonzini, 2023/03/02
- [PULL 21/62] i386/xen: handle VCPUOP_register_vcpu_info, Paolo Bonzini, 2023/03/02
- [PULL 25/62] i386/xen: implement HVMOP_set_evtchn_upcall_vector, Paolo Bonzini, 2023/03/02
- [PULL 26/62] i386/xen: implement HVMOP_set_param, Paolo Bonzini, 2023/03/02
- [PULL 18/62] i386/xen: implement XENMEM_add_to_physmap_batch, Paolo Bonzini, 2023/03/02
- [PULL 20/62] i386/xen: implement HYPERVISOR_vcpu_op, Paolo Bonzini, 2023/03/02