Re: [PATCH RFCv1 6/8] kvm: Add helper kvm_dirty_ring_init()

2023-02-09 Thread Gavin Shan 

On 2/9/23 9:11 AM, Juan Quintela wrote:

Gavin Shan  wrote:

Due to multiple capabilities associated with the dirty ring for different
architectures: KVM_CAP_DIRTY_{LOG_RING, LOG_RING_ACQ_REL} for x86 and
arm64 separately. There will be more to be done in order to support the
dirty ring for arm64.

Lets add helper kvm_dirty_ring_init() to enable the dirty ring. With this,
the code looks a bit clean.

No functional change intended.

Signed-off-by: Gavin Shan 
---
  accel/kvm/kvm-all.c | 73 -
  1 file changed, 46 insertions(+), 27 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 9ec117c441..399ef0f7e6 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1476,6 +1476,49 @@ static int kvm_dirty_ring_reaper_init(KVMState *s)
  return 0;
  }
  
+static int kvm_dirty_ring_init(KVMState *s)

+{
+uint64_t ring_bytes;
+int ret;
+
+/*
+ * Read the max supported pages. Fall back to dirty logging mode
+ * if the dirty ring isn't supported.
+ */
+ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
+if (ret <= 0) {
+warn_report("KVM dirty ring not available, using bitmap method");
+s->kvm_dirty_ring_size = 0;
+return 0;
+}
+
+ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
+if (ring_bytes > ret) {
+error_report("KVM dirty ring size %" PRIu32 " too big "
+ "(maximum is %ld).  Please use a smaller value.",
+ s->kvm_dirty_ring_size,
+ (long)ret / sizeof(struct kvm_dirty_gfn));
+ret = -EINVAL;
+goto out;
+}
+
+ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
+if (ret) {
+error_report("Enabling of KVM dirty ring failed: %s. "
+ "Suggested minimum value is 1024.", strerror(-ret));
+ret = -EIO;
+}
+
+out:
+if (ret) {
+s->kvm_dirty_ring_size = 0;
+} else {
+s->kvm_dirty_ring_bytes = ring_bytes;
+}
+
+return ret;
+}


If you split it, you don't need the goto.

static int kvm_dirty_ring_init(KVMState *s)
{
 s->kvm_dirty_ring_size = 0;
 /*
  * Read the max supported pages. Fall back to dirty logging mode
  * if the dirty ring isn't supported.
  */
 int ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
 if (ret <= 0) {
 warn_report("KVM dirty ring not available, using bitmap method");
 return 0;
 }

 uint64_t ring_bytes = s->kvm_dirty_ring_size * sizeof(struct 
kvm_dirty_gfn);
 if (ring_bytes > ret) {
 error_report("KVM dirty ring size %" PRIu32 " too big "
  "(maximum is %ld).  Please use a smaller value.",
  s->kvm_dirty_ring_size,
  (long)ret / sizeof(struct kvm_dirty_gfn));
 return -EINVAL;
 }

 ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
 if (ret) {
 error_report("Enabling of KVM dirty ring failed: %s. "
  "Suggested minimum value is 1024.", strerror(-ret));
 return -EIO;
 }

 s->kvm_dirty_ring_bytes = ring_bytes;
 return ret;
}



Ok, thanks for your review. The goto will be removed in next revision.





+
  static void kvm_region_add(MemoryListener *listener,
 MemoryRegionSection *section)
  {
@@ -2545,33 +2588,9 @@ static int kvm_init(MachineState *ms)
   * dirty logging mode
   */
  if (s->kvm_dirty_ring_size > 0) {
-uint64_t ring_bytes;
-
-ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
-
-/* Read the max supported pages */
-ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
-if (ret > 0) {
-if (ring_bytes > ret) {
-error_report("KVM dirty ring size %" PRIu32 " too big "
- "(maximum is %ld).  Please use a smaller value.",
- s->kvm_dirty_ring_size,
- (long)ret / sizeof(struct kvm_dirty_gfn));
-ret = -EINVAL;
-goto err;
-}
-
-ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
-if (ret) {
-error_report("Enabling of KVM dirty ring failed: %s. "
- "Suggested minimum value is 1024.", 
strerror(-ret));
-goto err;
-}
-
-s->kvm_dirty_ring_bytes = ring_bytes;
- } else {
- warn_report("KVM dirty ring not available, using bitmap method");
- s->kvm_dirty_ring_size = 0;
+ret = kvm_dirty_ring_init(s);
+if (ret < 0) {
+goto err;
  }
  }



Thanks,
Gavin

Re: [PATCH RFCv1 6/8] kvm: Add helper kvm_dirty_ring_init()

2023-02-08 Thread Juan Quintela 
Gavin Shan  wrote:
> Due to multiple capabilities associated with the dirty ring for different
> architectures: KVM_CAP_DIRTY_{LOG_RING, LOG_RING_ACQ_REL} for x86 and
> arm64 separately. There will be more to be done in order to support the
> dirty ring for arm64.
>
> Lets add helper kvm_dirty_ring_init() to enable the dirty ring. With this,
> the code looks a bit clean.
>
> No functional change intended.
>
> Signed-off-by: Gavin Shan 
> ---
>  accel/kvm/kvm-all.c | 73 -
>  1 file changed, 46 insertions(+), 27 deletions(-)
>
> diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> index 9ec117c441..399ef0f7e6 100644
> --- a/accel/kvm/kvm-all.c
> +++ b/accel/kvm/kvm-all.c
> @@ -1476,6 +1476,49 @@ static int kvm_dirty_ring_reaper_init(KVMState *s)
>  return 0;
>  }
>  
> +static int kvm_dirty_ring_init(KVMState *s)
> +{
> +uint64_t ring_bytes;
> +int ret;
> +
> +/*
> + * Read the max supported pages. Fall back to dirty logging mode
> + * if the dirty ring isn't supported.
> + */
> +ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
> +if (ret <= 0) {
> +warn_report("KVM dirty ring not available, using bitmap method");
> +s->kvm_dirty_ring_size = 0;
> +return 0;
> +}
> +
> +ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
> +if (ring_bytes > ret) {
> +error_report("KVM dirty ring size %" PRIu32 " too big "
> + "(maximum is %ld).  Please use a smaller value.",
> + s->kvm_dirty_ring_size,
> + (long)ret / sizeof(struct kvm_dirty_gfn));
> +ret = -EINVAL;
> +goto out;
> +}
> +
> +ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
> +if (ret) {
> +error_report("Enabling of KVM dirty ring failed: %s. "
> + "Suggested minimum value is 1024.", strerror(-ret));
> +ret = -EIO;
> +}
> +
> +out:
> +if (ret) {
> +s->kvm_dirty_ring_size = 0;
> +} else {
> +s->kvm_dirty_ring_bytes = ring_bytes;
> +}
> +
> +return ret;
> +}

If you split it, you don't need the goto.

static int kvm_dirty_ring_init(KVMState *s)
{
s->kvm_dirty_ring_size = 0;
/*
 * Read the max supported pages. Fall back to dirty logging mode
 * if the dirty ring isn't supported.
 */
int ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
if (ret <= 0) {
warn_report("KVM dirty ring not available, using bitmap method");
return 0;
}

uint64_t ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
if (ring_bytes > ret) {
error_report("KVM dirty ring size %" PRIu32 " too big "
 "(maximum is %ld).  Please use a smaller value.",
 s->kvm_dirty_ring_size,
 (long)ret / sizeof(struct kvm_dirty_gfn));
return -EINVAL;
}

ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
if (ret) {
error_report("Enabling of KVM dirty ring failed: %s. "
 "Suggested minimum value is 1024.", strerror(-ret));
return -EIO;
}

s->kvm_dirty_ring_bytes = ring_bytes;
return ret;
}



> +
>  static void kvm_region_add(MemoryListener *listener,
> MemoryRegionSection *section)
>  {
> @@ -2545,33 +2588,9 @@ static int kvm_init(MachineState *ms)
>   * dirty logging mode
>   */
>  if (s->kvm_dirty_ring_size > 0) {
> -uint64_t ring_bytes;
> -
> -ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
> -
> -/* Read the max supported pages */
> -ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
> -if (ret > 0) {
> -if (ring_bytes > ret) {
> -error_report("KVM dirty ring size %" PRIu32 " too big "
> - "(maximum is %ld).  Please use a smaller 
> value.",
> - s->kvm_dirty_ring_size,
> - (long)ret / sizeof(struct kvm_dirty_gfn));
> -ret = -EINVAL;
> -goto err;
> -}
> -
> -ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, 
> ring_bytes);
> -if (ret) {
> -error_report("Enabling of KVM dirty ring failed: %s. "
> - "Suggested minimum value is 1024.", 
> strerror(-ret));
> -goto err;
> -}
> -
> -s->kvm_dirty_ring_bytes = ring_bytes;
> - } else {
> - warn_report("KVM dirty ring not available, using bitmap 
> method");
> - s->kvm_dirty_ring_size = 0;
> +ret = kvm_dirty_ring_init(s);
> +if (ret < 0) {
> +goto err;
>  }
>  }

[PATCH RFCv1 6/8] kvm: Add helper kvm_dirty_ring_init()

2023-02-06 Thread Gavin Shan 
Due to multiple capabilities associated with the dirty ring for different
architectures: KVM_CAP_DIRTY_{LOG_RING, LOG_RING_ACQ_REL} for x86 and
arm64 separately. There will be more to be done in order to support the
dirty ring for arm64.

Lets add helper kvm_dirty_ring_init() to enable the dirty ring. With this,
the code looks a bit clean.

No functional change intended.

Signed-off-by: Gavin Shan 
---
 accel/kvm/kvm-all.c | 73 -
 1 file changed, 46 insertions(+), 27 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 9ec117c441..399ef0f7e6 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1476,6 +1476,49 @@ static int kvm_dirty_ring_reaper_init(KVMState *s)
 return 0;
 }
 
+static int kvm_dirty_ring_init(KVMState *s)
+{
+uint64_t ring_bytes;
+int ret;
+
+/*
+ * Read the max supported pages. Fall back to dirty logging mode
+ * if the dirty ring isn't supported.
+ */
+ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
+if (ret <= 0) {
+warn_report("KVM dirty ring not available, using bitmap method");
+s->kvm_dirty_ring_size = 0;
+return 0;
+}
+
+ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
+if (ring_bytes > ret) {
+error_report("KVM dirty ring size %" PRIu32 " too big "
+ "(maximum is %ld).  Please use a smaller value.",
+ s->kvm_dirty_ring_size,
+ (long)ret / sizeof(struct kvm_dirty_gfn));
+ret = -EINVAL;
+goto out;
+}
+
+ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
+if (ret) {
+error_report("Enabling of KVM dirty ring failed: %s. "
+ "Suggested minimum value is 1024.", strerror(-ret));
+ret = -EIO;
+}
+
+out:
+if (ret) {
+s->kvm_dirty_ring_size = 0;
+} else {
+s->kvm_dirty_ring_bytes = ring_bytes;
+}
+
+return ret;
+}
+
 static void kvm_region_add(MemoryListener *listener,
MemoryRegionSection *section)
 {
@@ -2545,33 +2588,9 @@ static int kvm_init(MachineState *ms)
  * dirty logging mode
  */
 if (s->kvm_dirty_ring_size > 0) {
-uint64_t ring_bytes;
-
-ring_bytes = s->kvm_dirty_ring_size * sizeof(struct kvm_dirty_gfn);
-
-/* Read the max supported pages */
-ret = kvm_vm_check_extension(s, KVM_CAP_DIRTY_LOG_RING);
-if (ret > 0) {
-if (ring_bytes > ret) {
-error_report("KVM dirty ring size %" PRIu32 " too big "
- "(maximum is %ld).  Please use a smaller value.",
- s->kvm_dirty_ring_size,
- (long)ret / sizeof(struct kvm_dirty_gfn));
-ret = -EINVAL;
-goto err;
-}
-
-ret = kvm_vm_enable_cap(s, KVM_CAP_DIRTY_LOG_RING, 0, ring_bytes);
-if (ret) {
-error_report("Enabling of KVM dirty ring failed: %s. "
- "Suggested minimum value is 1024.", 
strerror(-ret));
-goto err;
-}
-
-s->kvm_dirty_ring_bytes = ring_bytes;
- } else {
- warn_report("KVM dirty ring not available, using bitmap method");
- s->kvm_dirty_ring_size = 0;
+ret = kvm_dirty_ring_init(s);
+if (ret < 0) {
+goto err;
 }
 }
 
-- 
2.23.0