s390_virtio_hypercall can trigger IO events and interrupts, most notably
when using virtio-ccw devices.
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
---
target/s390x/misc_helper.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c
index 4946b56ab3..aec737d707 100644
--- a/target/s390x/misc_helper.c
+++ b/target/s390x/misc_helper.c
@@ -307,7 +307,9 @@ void HELPER(diag)(CPUS390XState *env, uint32_t r1, uint32_t r3, uint32_t num)
switch (num) {
case 0x500:
/* KVM hypercall */
+ qemu_mutex_lock_iothread();
r = s390_virtio_hypercall(env);
+ qemu_mutex_unlock_iothread();
break;
case 0x44:
/* yield */
--
2.11.0
Hi Aurelien! Why don't lock inside s390_virtio_hypercall() directly round the diag500 dispatch call? regards, Phil. On 04/23/2017 07:32 PM, Aurelien Jarno wrote: > s390_virtio_hypercall can trigger IO events and interrupts, most notably > when using virtio-ccw devices. > > Reviewed-by: Alexander Graf <agraf@suse.de> > Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> > --- > target/s390x/misc_helper.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/target/s390x/misc_helper.c b/target/s390x/misc_helper.c > index 4946b56ab3..aec737d707 100644 > --- a/target/s390x/misc_helper.c > +++ b/target/s390x/misc_helper.c > @@ -307,7 +307,9 @@ void HELPER(diag)(CPUS390XState *env, uint32_t r1, uint32_t r3, uint32_t num) > switch (num) { > case 0x500: > /* KVM hypercall */ > + qemu_mutex_lock_iothread(); > r = s390_virtio_hypercall(env); > + qemu_mutex_unlock_iothread(); > break; > case 0x44: > /* yield */ >
On 2017-04-23 19:38, Philippe Mathieu-Daudé wrote: > Hi Aurelien! > > Why don't lock inside s390_virtio_hypercall() directly round the diag500 > dispatch call? s390_virtio_hypercall is shared between TCG and KVM. For KVM the lock is already done before calling s390_virtio_hypercall in kvm_arch_handle_exit. -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurelien@aurel32.net http://www.aurel32.net
On 04/23/2017 07:47 PM, Aurelien Jarno wrote: > On 2017-04-23 19:38, Philippe Mathieu-Daudé wrote: >> Hi Aurelien! >> >> Why don't lock inside s390_virtio_hypercall() directly round the diag500 >> dispatch call? > > s390_virtio_hypercall is shared between TCG and KVM. For KVM the lock is > already done before calling s390_virtio_hypercall in kvm_arch_handle_exit. Fair enough! Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
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