mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

xive/kvm: Trigger interrupts from userspace

Browse Source 
When using the XIVE KVM device, the trigger page is directly accessible
in QEMU. Unlike with XICS, no need to ask KVM to fire the interrupt. A
simple store on the trigger page does the job.

Just call xive_esb_trigger().

This may improve performance of emulated devices that go through
qemu_set_irq(), eg. virtio devices created with ioeventfd=off or
configured by the guest to use LSI interrupts, which aren't really
recommended setups.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <157408992731.494439.3405812941731584740.stgit@bahia.lan>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Greg Kurz 2019-11-18 16:12:07 +01:00 committed by David Gibson
parent 7aa22e1809
commit 58246041d3
1 changed files with 2 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
hw/intc/spapr_xive_kvm.c
View File

@ -354,32 +354,20 @@ static void kvmppc_xive_source_get_state(XiveSource *xsrc)
void kvmppc_xive_source_set_irq(void *opaque, int srcno, int val) void kvmppc_xive_source_set_irq(void *opaque, int srcno, int val)
{ {
XiveSource *xsrc = opaque; XiveSource *xsrc = opaque;
SpaprXive *xive = SPAPR_XIVE(xsrc->xive);
struct kvm_irq_level args;
int rc;
/* The KVM XIVE device should be in use */
assert(xive->fd != -1);
args.irq = srcno;
if (!xive_source_irq_is_lsi(xsrc, srcno)) { if (!xive_source_irq_is_lsi(xsrc, srcno)) {
if (!val) { if (!val) {
return; return;
} }
args.level = KVM_INTERRUPT_SET;
} else { } else {
if (val) { if (val) {
xsrc->status[srcno] |= XIVE_STATUS_ASSERTED; xsrc->status[srcno] |= XIVE_STATUS_ASSERTED;
args.level = KVM_INTERRUPT_SET_LEVEL;
} else { } else {
xsrc->status[srcno] &= ~XIVE_STATUS_ASSERTED; xsrc->status[srcno] &= ~XIVE_STATUS_ASSERTED;
args.level = KVM_INTERRUPT_UNSET;
} }
} }
rc = kvm_vm_ioctl(kvm_state, KVM_IRQ_LINE, &args);
if (rc < 0) { xive_esb_trigger(xsrc, srcno);
error_report("XIVE: kvm_irq_line() failed : %s", strerror(errno));
}
} }
/* /*