From: lon...@linuxonhyperv.com <lon...@linuxonhyperv.com>
>
> Interrupt and monitor pages should be in Hyper-V page size (4k bytes).
> This can be different to the system page size.
I'm curious about this change. Since Patch 1 of the series changes
the allocations to be the full PAGE_SIZE, what does it mean to set
the mapping size to less than a full page (in the case PAGE_SIZE >
HV_HYP_PAGE_SIZE)? mmap can only map full PAGE_SIZE pages,
so uio_mmap() rounds up the INT_PAGE_MAP and MON_PAGE_MAP
sizes to PAGE_SIZE when checking the validity of the mmap
parameters.
The changes in this patch do ensure that the INT_PAGE_MAP and
MON_PAGE_MAP "maps" entries in sysfs always show the size as
4096 even if the full PAGE_SIZE is actually mapped, but I'm not sure
if that difference is good or bad.
Michael
>
> Cc: sta...@vger.kernel.org
> Fixes: 95096f2fbd10 ("uio-hv-generic: new userspace i/o driver for VMBus")
> Signed-off-by: Long Li <lon...@microsoft.com>
> ---
> drivers/uio/uio_hv_generic.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
> index 1b19b5647495..08385b04c4ab 100644
> --- a/drivers/uio/uio_hv_generic.c
> +++ b/drivers/uio/uio_hv_generic.c
> @@ -287,13 +287,13 @@ hv_uio_probe(struct hv_device *dev,
> pdata->info.mem[INT_PAGE_MAP].name = "int_page";
> pdata->info.mem[INT_PAGE_MAP].addr
> = (uintptr_t)vmbus_connection.int_page;
> - pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
> + pdata->info.mem[INT_PAGE_MAP].size = HV_HYP_PAGE_SIZE;
> pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
>
> pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
> pdata->info.mem[MON_PAGE_MAP].addr
> = (uintptr_t)vmbus_connection.monitor_pages[1];
> - pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
> + pdata->info.mem[MON_PAGE_MAP].size = HV_HYP_PAGE_SIZE;
> pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
>
> if (channel->device_id == HV_NIC) {
> --
> 2.34.1
>
