* [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true
@ 2020-10-17 21:01 Elena Afanasova
2020-10-17 21:01 ` [PATCH] softmmu/memory: fix memory_region_ioeventfd_equal() Elena Afanasova
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Elena Afanasova @ 2020-10-17 21:01 UTC (permalink / raw)
To: qemu-devel; +Cc: Elena Afanasova, pbonzini, stefanha
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Elena Afanasova <eafanasova@gmail.com>
---
accel/kvm/kvm-all.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 9ef5daf4c5..baaa54249d 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -2239,8 +2239,10 @@ static int kvm_init(MachineState *ms)
kvm_memory_listener_register(s, &s->memory_listener,
&address_space_memory, 0);
- memory_listener_register(&kvm_io_listener,
- &address_space_io);
+ if (kvm_eventfds_allowed) {
+ memory_listener_register(&kvm_io_listener,
+ &address_space_io);
+ }
memory_listener_register(&kvm_coalesced_pio_listener,
&address_space_io);
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH] softmmu/memory: fix memory_region_ioeventfd_equal()
2020-10-17 21:01 [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true Elena Afanasova
@ 2020-10-17 21:01 ` Elena Afanasova
2020-10-19 10:25 ` Stefan Hajnoczi
2020-10-19 10:05 ` [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true Stefan Hajnoczi
2020-10-20 15:40 ` Stefan Hajnoczi
2 siblings, 1 reply; 5+ messages in thread
From: Elena Afanasova @ 2020-10-17 21:01 UTC (permalink / raw)
To: qemu-devel; +Cc: Elena Afanasova, pbonzini, stefanha
Eventfd can be registered with a zero length when fast_mmio is true.
Handle this case properly when dispatching through QEMU.
Signed-off-by: Elena Afanasova <eafanasova@gmail.com>
---
softmmu/memory.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/softmmu/memory.c b/softmmu/memory.c
index 403ff3abc9..3ca2154a64 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -203,10 +203,17 @@ static bool memory_region_ioeventfd_before(MemoryRegionIoeventfd *a,
}
static bool memory_region_ioeventfd_equal(MemoryRegionIoeventfd *a,
- MemoryRegionIoeventfd *b)
-{
- return !memory_region_ioeventfd_before(a, b)
- && !memory_region_ioeventfd_before(b, a);
+ MemoryRegionIoeventfd *mrb)
+{
+ if (int128_eq(a->addr.start, mrb->addr.start) &&
+ (!int128_nz(mrb->addr.size) ||
+ int128_eq(a->addr.size, mrb->addr.size)) &&
+ (a->match_data == mrb->match_data) &&
+ ((mrb->match_data && (a->data == mrb->data)) || !mrb->match_data) &&
+ (a->e == mrb->e))
+ return true;
+
+ return false;
}
/* Range of memory in the global map. Addresses are absolute. */
--
2.25.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] softmmu/memory: fix memory_region_ioeventfd_equal()
2020-10-17 21:01 ` [PATCH] softmmu/memory: fix memory_region_ioeventfd_equal() Elena Afanasova
@ 2020-10-19 10:25 ` Stefan Hajnoczi
0 siblings, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2020-10-19 10:25 UTC (permalink / raw)
To: Elena Afanasova; +Cc: pbonzini, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 2226 bytes --]
On Sat, Oct 17, 2020 at 02:01:02PM -0700, Elena Afanasova wrote:
> Eventfd can be registered with a zero length when fast_mmio is true.
> Handle this case properly when dispatching through QEMU.
>
> Signed-off-by: Elena Afanasova <eafanasova@gmail.com>
> ---
> softmmu/memory.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/softmmu/memory.c b/softmmu/memory.c
> index 403ff3abc9..3ca2154a64 100644
> --- a/softmmu/memory.c
> +++ b/softmmu/memory.c
> @@ -203,10 +203,17 @@ static bool memory_region_ioeventfd_before(MemoryRegionIoeventfd *a,
> }
>
> static bool memory_region_ioeventfd_equal(MemoryRegionIoeventfd *a,
> - MemoryRegionIoeventfd *b)
> -{
> - return !memory_region_ioeventfd_before(a, b)
> - && !memory_region_ioeventfd_before(b, a);
> + MemoryRegionIoeventfd *mrb)
Why rename b -> mrb?
> +{
> + if (int128_eq(a->addr.start, mrb->addr.start) &&
> + (!int128_nz(mrb->addr.size) ||
> + int128_eq(a->addr.size, mrb->addr.size)) &&
> + (a->match_data == mrb->match_data) &&
> + ((mrb->match_data && (a->data == mrb->data)) || !mrb->match_data) &&
> + (a->e == mrb->e))
> + return true;
The kernel behaves differently in that a and b are symmetric:
static bool
ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
{
struct _ioeventfd *_p;
list_for_each_entry(_p, &kvm->ioeventfds, list)
if (_p->bus_idx == p->bus_idx &&
_p->addr == p->addr &&
(!_p->length || !p->length ||
(_p->length == p->length &&
(_p->wildcard || p->wildcard ||
_p->datamatch == p->datamatch))))
return true;
return false;
}
For example, if a->addr.size == 0 then the ioeventfd matches whereas
this patch only does it for b.
Please match the kernel behavior.
A different approach is setting ioeventfd.addr.size to zero when
mr->ioeventfds[i].addr.size is zero in the
memory_region_dispatch_write_eventfds() loop. That way
memory_region_ioeventfd_equal() doesn't need to be modified.
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true
2020-10-17 21:01 [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true Elena Afanasova
2020-10-17 21:01 ` [PATCH] softmmu/memory: fix memory_region_ioeventfd_equal() Elena Afanasova
@ 2020-10-19 10:05 ` Stefan Hajnoczi
2020-10-20 15:40 ` Stefan Hajnoczi
2 siblings, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2020-10-19 10:05 UTC (permalink / raw)
To: Elena Afanasova; +Cc: pbonzini, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 1410 bytes --]
On Sat, Oct 17, 2020 at 02:01:01PM -0700, Elena Afanasova wrote:
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Elena Afanasova <eafanasova@gmail.com>
> ---
> accel/kvm/kvm-all.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
Additional information for the commit description:
MMIO eventfd_add/del are only registered when kvm_eventfds_allowed is
true but for PIO they are registered unconditionally. This is a bug
because kvm.ko ioeventfd should not be used if kvm_eventfds_allowed is
false.
This issue is a latent bug because ioeventfd is usually available when
KVM is enabled.
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 9ef5daf4c5..baaa54249d 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -2239,8 +2239,10 @@ static int kvm_init(MachineState *ms)
>
> kvm_memory_listener_register(s, &s->memory_listener,
> &address_space_memory, 0);
> - memory_listener_register(&kvm_io_listener,
> - &address_space_io);
> + if (kvm_eventfds_allowed) {
> + memory_listener_register(&kvm_io_listener,
> + &address_space_io);
> + }
> memory_listener_register(&kvm_coalesced_pio_listener,
> &address_space_io);
>
> --
> 2.25.1
>
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^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true
2020-10-17 21:01 [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true Elena Afanasova
2020-10-17 21:01 ` [PATCH] softmmu/memory: fix memory_region_ioeventfd_equal() Elena Afanasova
2020-10-19 10:05 ` [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true Stefan Hajnoczi
@ 2020-10-20 15:40 ` Stefan Hajnoczi
2 siblings, 0 replies; 5+ messages in thread
From: Stefan Hajnoczi @ 2020-10-20 15:40 UTC (permalink / raw)
To: Elena Afanasova; +Cc: pbonzini, qemu-devel
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On Sat, Oct 17, 2020 at 02:01:01PM -0700, Elena Afanasova wrote:
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Elena Afanasova <eafanasova@gmail.com>
> ---
> accel/kvm/kvm-all.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
Thanks, applied just this patch to my block-next tree:
https://github.com/stefanha/qemu/commits/block-next
Stefan
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2020-10-17 21:01 [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true Elena Afanasova
2020-10-17 21:01 ` [PATCH] softmmu/memory: fix memory_region_ioeventfd_equal() Elena Afanasova
2020-10-19 10:25 ` Stefan Hajnoczi
2020-10-19 10:05 ` [PATCH] accel/kvm: add PIO ioeventfds only in case kvm_eventfds_allowed is true Stefan Hajnoczi
2020-10-20 15:40 ` Stefan Hajnoczi
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