Re: [PATCH RFC 3/3] pci-testdev: add RO pages for ioeventfd

[Gonglei <arei.gonglei@huawei.com>]

On 2015/8/30 17:20, Michael S. Tsirkin wrote:
> This seems hackish - would it be better to create this region
> automatically within kvm? Suggestions are welcome.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  hw/misc/pci-testdev.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/hw/misc/pci-testdev.c b/hw/misc/pci-testdev.c
> index 94141a3..55efc32 100644
> --- a/hw/misc/pci-testdev.c
> +++ b/hw/misc/pci-testdev.c
> @@ -21,6 +21,7 @@
>  #include "hw/pci/pci.h"
>  #include "qemu/event_notifier.h"
>  #include "qemu/osdep.h"
> +#include <sys/mman.h>
>  
>  typedef struct PCITestDevHdr {
>      uint8_t test;
> @@ -82,11 +83,13 @@ typedef struct PCITestDevState {
>      PCIDevice parent_obj;
>      /*< public >*/
>  
> +    MemoryRegion zeromr;
>      MemoryRegion mmio;
>      MemoryRegion mbar;
>      MemoryRegion portio;
>      IOTest *tests;
>      int current;
> +    void *zero;
>  } PCITestDevState;
>  
>  #define TYPE_PCI_TEST_DEV "pci-testdev"
> @@ -242,6 +245,11 @@ static void pci_testdev_realize(PCIDevice *pci_dev, Error **errp)
>      uint8_t *pci_conf;
>      char *name;
>      int r, i;
> +    d->zero = mmap(NULL, IOTEST_MEMSIZE * 2, PROT_READ,
> +                         MAP_SHARED | MAP_ANONYMOUS, -1, 0);
> +

Do we need think about hotplugging pci-testdev ? If yes, then we should release some resources
when hot-unplug a pci-testdev device:
munmap(d->zero, ...)
memory_region_del_subregion(&d->mbar, &d->mmio)
...

Regards,
-Gonglei

> +    memory_region_init_ram_ptr(&d->zeromr, OBJECT(d), "pci-testdev-zero", 0x1000, d->zero);
> +    memory_region_set_readonly(&d->zeromr, true);
>  
>      pci_conf = pci_dev->config;
>  
> @@ -286,6 +294,11 @@ static void pci_testdev_realize(PCIDevice *pci_dev, Error **errp)
>              test->hasnotifier = false;
>              continue;
>          }
> +
> +        if (test->hasnotifier && !test->size) {
> +            memory_region_add_subregion_overlap(&d->mbar, le32_to_cpu(test->hdr->offset),
> +                                                &d->zeromr, 2 /* prio */);
> +        }
>          r = event_notifier_init(&test->notifier, 0);
>          assert(r >= 0);
>          test->hasnotifier = true;
>