Re: [PATCH] hw/nvme: be more careful when deasserting IRQs
Patchew URL:
https://patchew.org/QEMU/20210610114624.304681-1-jakub.jer...@kernkonzept.com/
Hi,
This series seems to have some coding style problems. See output below for
more information:
Type: series
Message-id: 20210610114624.304681-1-jakub.jer...@kernkonzept.com
Subject: [PATCH] hw/nvme: be more careful when deasserting IRQs
=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===
Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
* [new tag] patchew/20210610132505.5827-1-peter.mayd...@linaro.org ->
patchew/20210610132505.5827-1-peter.mayd...@linaro.org
* [new tag]
patchew/20210614135429.56475-1-jakub.jer...@kernkonzept.com ->
patchew/20210614135429.56475-1-jakub.jer...@kernkonzept.com
Switched to a new branch 'test'
aacc285 hw/nvme: be more careful when deasserting IRQs
=== OUTPUT BEGIN ===
ERROR: braces {} are necessary for all arms of this statement
#34: FILE: hw/nvme/ctrl.c:485:
+if (q && q->vector == cq->vector && q->head != q->tail)
[...]
total: 1 errors, 0 warnings, 39 lines checked
Commit aacc285402f0 (hw/nvme: be more careful when deasserting IRQs) has style
problems, please review. If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
=== OUTPUT END ===
Test command exited with code: 1
The full log is available at
http://patchew.org/logs/20210610114624.304681-1-jakub.jer...@kernkonzept.com/testing.checkpatch/?type=message.
---
Email generated automatically by Patchew [https://patchew.org/].
Please send your feedback to patchew-de...@redhat.com
Re: [PATCH] hw/nvme: be more careful when deasserting IRQs
On 6/10/21 8:14 PM, Klaus Jensen wrote:
On Jun 10 13:46, Jakub Jermář wrote:
An IRQ vector used by a completion queue cannot be deasserted without
first checking if the same vector does not need to stay asserted for
some other completion queue.
Signed-off-by: Jakub Jermar
---
hw/nvme/ctrl.c | 21 +++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index 0bcaf7192f..c0980929eb 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -473,6 +473,21 @@ static void nvme_irq_deassert(NvmeCtrl *n,
NvmeCQueue *cq)
}
}
+/*
+ * Check if the vector used by the cq can be deasserted, i.e. it
needn't be
+ * asserted for some other cq.
+ */
+static bool nvme_irq_can_deassert(NvmeCtrl *n, NvmeCQueue *cq)
+{
+ for (unsigned qid = 0; qid < n->params.max_ioqpairs + 1; qid++) {
+ NvmeCQueue *q = n->cq[qid];
+
+ if (q && q->vector == cq->vector && q->head != q->tail)
+ return false; /* some queue needs this to stay asserted */
+ }
+ return true;
+}
+
static void nvme_req_clear(NvmeRequest *req)
{
req->ns = NULL;
@@ -4089,7 +4104,9 @@ static uint16_t nvme_del_cq(NvmeCtrl *n,
NvmeRequest *req)
trace_pci_nvme_err_invalid_del_cq_notempty(qid);
return NVME_INVALID_QUEUE_DEL;
}
- nvme_irq_deassert(n, cq);
+ if (nvme_irq_can_deassert(n, cq)) {
+ nvme_irq_deassert(n, cq);
+ }
trace_pci_nvme_del_cq(qid);
nvme_free_cq(cq, n);
return NVME_SUCCESS;
@@ -5757,7 +5774,7 @@ static void nvme_process_db(NvmeCtrl *n, hwaddr
addr, int val)
timer_mod(cq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)
+ 500);
}
- if (cq->tail == cq->head) {
+ if (nvme_irq_can_deassert(n, cq)) {
nvme_irq_deassert(n, cq);
}
} else {
--
2.31.1
This is actually an artifact of commit ca247d35098d3 ("hw/block/nvme:
fix pin-based interrupt behavior") that I did a year ago. Prior to that
fix, the completion queue id was used to index the internal IS register
(irq_status), which, while wrong spec-wise, had the effect of...
actually working.
Anyway, I agree that the logic is flawed right now, since we should only
deassert when all outstanding cqe's have been acknowledged by the host.
nvme_irq_can_deassert should be guarded with a check on msix_enabled(),
but in any case I am not happy about looping over all completion queues
on each cq doorbell write. I think this can be ref counted? I.e.
decrement when cq->tail == cq->head on the cq doorbell write and
increment only when going from empty to non-empty in nvme_post_cqes().
I reworked this to use reference counting in v2.
Jakub
Re: [PATCH] hw/nvme: be more careful when deasserting IRQs
On Jun 10 13:46, Jakub Jermář wrote:
An IRQ vector used by a completion queue cannot be deasserted without
first checking if the same vector does not need to stay asserted for
some other completion queue.
Signed-off-by: Jakub Jermar
---
hw/nvme/ctrl.c | 21 +++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index 0bcaf7192f..c0980929eb 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -473,6 +473,21 @@ static void nvme_irq_deassert(NvmeCtrl *n, NvmeCQueue *cq)
}
}
+/*
+ * Check if the vector used by the cq can be deasserted, i.e. it needn't be
+ * asserted for some other cq.
+ */
+static bool nvme_irq_can_deassert(NvmeCtrl *n, NvmeCQueue *cq)
+{
+for (unsigned qid = 0; qid < n->params.max_ioqpairs + 1; qid++) {
+NvmeCQueue *q = n->cq[qid];
+
+if (q && q->vector == cq->vector && q->head != q->tail)
+return false; /* some queue needs this to stay asserted */
+}
+return true;
+}
+
static void nvme_req_clear(NvmeRequest *req)
{
req->ns = NULL;
@@ -4089,7 +4104,9 @@ static uint16_t nvme_del_cq(NvmeCtrl *n, NvmeRequest *req)
trace_pci_nvme_err_invalid_del_cq_notempty(qid);
return NVME_INVALID_QUEUE_DEL;
}
-nvme_irq_deassert(n, cq);
+if (nvme_irq_can_deassert(n, cq)) {
+nvme_irq_deassert(n, cq);
+}
trace_pci_nvme_del_cq(qid);
nvme_free_cq(cq, n);
return NVME_SUCCESS;
@@ -5757,7 +5774,7 @@ static void nvme_process_db(NvmeCtrl *n, hwaddr addr, int
val)
timer_mod(cq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 500);
}
-if (cq->tail == cq->head) {
+if (nvme_irq_can_deassert(n, cq)) {
nvme_irq_deassert(n, cq);
}
} else {
--
2.31.1
This is actually an artifact of commit ca247d35098d3 ("hw/block/nvme:
fix pin-based interrupt behavior") that I did a year ago. Prior to that
fix, the completion queue id was used to index the internal IS register
(irq_status), which, while wrong spec-wise, had the effect of...
actually working.
Anyway, I agree that the logic is flawed right now, since we should only
deassert when all outstanding cqe's have been acknowledged by the host.
nvme_irq_can_deassert should be guarded with a check on msix_enabled(),
but in any case I am not happy about looping over all completion queues
on each cq doorbell write. I think this can be ref counted? I.e.
decrement when cq->tail == cq->head on the cq doorbell write and
increment only when going from empty to non-empty in nvme_post_cqes().
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Re: [PATCH] hw/nvme: be more careful when deasserting IRQs
+cc qemu-block, maintainers
On Jun 10 13:46, Jakub Jermář wrote:
An IRQ vector used by a completion queue cannot be deasserted without
first checking if the same vector does not need to stay asserted for
some other completion queue.
Signed-off-by: Jakub Jermar
---
hw/nvme/ctrl.c | 21 +++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c
index 0bcaf7192f..c0980929eb 100644
--- a/hw/nvme/ctrl.c
+++ b/hw/nvme/ctrl.c
@@ -473,6 +473,21 @@ static void nvme_irq_deassert(NvmeCtrl *n, NvmeCQueue *cq)
}
}
+/*
+ * Check if the vector used by the cq can be deasserted, i.e. it needn't be
+ * asserted for some other cq.
+ */
+static bool nvme_irq_can_deassert(NvmeCtrl *n, NvmeCQueue *cq)
+{
+for (unsigned qid = 0; qid < n->params.max_ioqpairs + 1; qid++) {
+NvmeCQueue *q = n->cq[qid];
+
+if (q && q->vector == cq->vector && q->head != q->tail)
+return false; /* some queue needs this to stay asserted */
+}
+return true;
+}
+
static void nvme_req_clear(NvmeRequest *req)
{
req->ns = NULL;
@@ -4089,7 +4104,9 @@ static uint16_t nvme_del_cq(NvmeCtrl *n, NvmeRequest *req)
trace_pci_nvme_err_invalid_del_cq_notempty(qid);
return NVME_INVALID_QUEUE_DEL;
}
-nvme_irq_deassert(n, cq);
+if (nvme_irq_can_deassert(n, cq)) {
+nvme_irq_deassert(n, cq);
+}
trace_pci_nvme_del_cq(qid);
nvme_free_cq(cq, n);
return NVME_SUCCESS;
@@ -5757,7 +5774,7 @@ static void nvme_process_db(NvmeCtrl *n, hwaddr addr, int
val)
timer_mod(cq->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 500);
}
-if (cq->tail == cq->head) {
+if (nvme_irq_can_deassert(n, cq)) {
nvme_irq_deassert(n, cq);
}
} else {
--
2.31.1
--
One of us - No more doubt, silence or taboo about mental illness.
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