[Qemu-devel] [PATCH] pci-testdev: fast mmio support

[Qemu-devel] [PATCH] pci-testdev: fast mmio support

[Michael S. Tsirkin]

Teach PCI testdev to use fast MMIO when kvm makes it available.

Before:
    mmio-wildcard-eventfd:pci-mem 2271
After:
    mmio-wildcard-eventfd:pci-mem 1218

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/misc/pci-testdev.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/misc/pci-testdev.c b/hw/misc/pci-testdev.c
index 5df9089..2f2e989 100644
--- a/hw/misc/pci-testdev.c
+++ b/hw/misc/pci-testdev.c
@@ -239,6 +239,7 @@ static void pci_testdev_realize(PCIDevice *pci_dev, Error **errp)
     uint8_t *pci_conf;
     char *name;
     int r, i;
+    bool fastmmio = kvm_ioeventfd_any_length_enabled();
 
     pci_conf = pci_dev->config;
 
@@ -261,8 +262,12 @@ static void pci_testdev_realize(PCIDevice *pci_dev, Error **errp)
         memcpy(test->hdr->name, name, strlen(name) + 1);
         g_free(name);
         test->hdr->offset = cpu_to_le32(IOTEST_SIZE(i) + i * IOTEST_ACCESS_WIDTH);
-        test->size = IOTEST_ACCESS_WIDTH;
         test->match_data = strcmp(IOTEST_TEST(i), "wildcard-eventfd");
+        if (fastmmio && IOTEST_IS_MEM(i) && !test->match_data) {
+            test->size = 0;
+        } else {
+            test->size = IOTEST_ACCESS_WIDTH;
+        }
         test->hdr->test = i;
         test->hdr->data = test->match_data ? IOTEST_DATAMATCH : IOTEST_NOMATCH;
         test->hdr->width = IOTEST_ACCESS_WIDTH;
-- 
MST

Re: [Qemu-devel] [PATCH] pci-testdev: fast mmio support

[Paolo Bonzini]

On 24/03/2016 14:10, Michael S. Tsirkin wrote:
> Teach PCI testdev to use fast MMIO when kvm makes it available.
> 
> Before:
>     mmio-wildcard-eventfd:pci-mem 2271
> After:
>     mmio-wildcard-eventfd:pci-mem 1218
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  hw/misc/pci-testdev.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/misc/pci-testdev.c b/hw/misc/pci-testdev.c
> index 5df9089..2f2e989 100644
> --- a/hw/misc/pci-testdev.c
> +++ b/hw/misc/pci-testdev.c
> @@ -239,6 +239,7 @@ static void pci_testdev_realize(PCIDevice *pci_dev, Error **errp)
>      uint8_t *pci_conf;
>      char *name;
>      int r, i;
> +    bool fastmmio = kvm_ioeventfd_any_length_enabled();
>  
>      pci_conf = pci_dev->config;
>  
> @@ -261,8 +262,12 @@ static void pci_testdev_realize(PCIDevice *pci_dev, Error **errp)
>          memcpy(test->hdr->name, name, strlen(name) + 1);
>          g_free(name);
>          test->hdr->offset = cpu_to_le32(IOTEST_SIZE(i) + i * IOTEST_ACCESS_WIDTH);
> -        test->size = IOTEST_ACCESS_WIDTH;
>          test->match_data = strcmp(IOTEST_TEST(i), "wildcard-eventfd");
> +        if (fastmmio && IOTEST_IS_MEM(i) && !test->match_data) {
> +            test->size = 0;
> +        } else {
> +            test->size = IOTEST_ACCESS_WIDTH;
> +        }
>          test->hdr->test = i;
>          test->hdr->data = test->match_data ? IOTEST_DATAMATCH : IOTEST_NOMATCH;
>          test->hdr->width = IOTEST_ACCESS_WIDTH;
> 

Acked-by: Paolo Bonzini <pbonzini@redhat.com>