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[PATCH v7 12/51] i386/xen: Implement SCHEDOP_poll and SCHEDOP_yield
From: |
David Woodhouse |
Subject: |
[PATCH v7 12/51] i386/xen: Implement SCHEDOP_poll and SCHEDOP_yield |
Date: |
Mon, 16 Jan 2023 21:57:26 +0000 |
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 5f2b55ef10..6584a15bab 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -227,6 +227,19 @@ 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;
}
--
2.39.0
- [PATCH v7 09/51] i386/xen: handle guest hypercalls, (continued)
- [PATCH v7 09/51] i386/xen: handle guest hypercalls, David Woodhouse, 2023/01/16
- [PATCH v7 16/51] i386/xen: implement HYPERVISOR_memory_op, David Woodhouse, 2023/01/16
- [PATCH v7 37/51] hw/xen: Implement EVTCHNOP_reset, David Woodhouse, 2023/01/16
- [PATCH v7 35/51] hw/xen: Implement EVTCHNOP_bind_interdomain, David Woodhouse, 2023/01/16
- [PATCH v7 41/51] kvm/i386: Add xen-gnttab-max-frames property, David Woodhouse, 2023/01/16
- [PATCH v7 05/51] i386/kvm: handle Xen HVM cpuid leaves, David Woodhouse, 2023/01/16
- [PATCH v7 39/51] hw/xen: Support HVM_PARAM_CALLBACK_TYPE_GSI callback, David Woodhouse, 2023/01/16
- [PATCH v7 47/51] i386/xen: Reserve Xen special pages for console, xenstore rings, David Woodhouse, 2023/01/16
- [PATCH v7 30/51] hw/xen: Implement EVTCHNOP_unmask, David Woodhouse, 2023/01/16
- [PATCH v7 17/51] i386/xen: implement XENMEM_add_to_physmap_batch, David Woodhouse, 2023/01/16
- [PATCH v7 12/51] i386/xen: Implement SCHEDOP_poll and SCHEDOP_yield,
David Woodhouse <=
- [PATCH v7 21/51] i386/xen: handle VCPUOP_register_vcpu_time_info, David Woodhouse, 2023/01/16
- [PATCH v7 11/51] i386/xen: implement HYPERVISOR_sched_op, SCHEDOP_shutdown, David Woodhouse, 2023/01/16
- [PATCH v7 13/51] hw/xen: Add xen_overlay device for emulating shared xenheap pages, David Woodhouse, 2023/01/16
- [PATCH v7 44/51] i386/xen: Implement HYPERVISOR_grant_table_op and GNTTABOP_[gs]et_verson, David Woodhouse, 2023/01/16
- [PATCH v7 48/51] i386/xen: handle HVMOP_get_param, David Woodhouse, 2023/01/16
- [PATCH v7 34/51] hw/xen: Implement EVTCHNOP_alloc_unbound, David Woodhouse, 2023/01/16
- [PATCH v7 10/51] i386/xen: implement HYPERVISOR_xen_version, David Woodhouse, 2023/01/16
- [PATCH v7 46/51] i386/xen: handle PV timer hypercalls, David Woodhouse, 2023/01/16
- [PATCH v7 27/51] i386/xen: Add support for Xen event channel delivery to vCPU, David Woodhouse, 2023/01/16