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Re: [Qemu-devel] [PATCH 2/3] xenfb: Add option to use grant ref for shar
From: |
Stefano Stabellini |
Subject: |
Re: [Qemu-devel] [PATCH 2/3] xenfb: Add option to use grant ref for shared page. |
Date: |
Thu, 11 Sep 2014 02:01:25 +0100 |
User-agent: |
Alpine 2.02 (DEB 1266 2009-07-14) |
On Wed, 10 Sep 2014, Owen smith wrote:
> The vkbd device should be able to use a grant reference to map the
> shared page.
>
> Signed-off-by: Owen smith <address@hidden>
> ---
> hw/display/xenfb.c | 39 +++++++++++++++++++++++++++++----------
> 1 file changed, 29 insertions(+), 10 deletions(-)
>
> diff --git a/hw/display/xenfb.c b/hw/display/xenfb.c
> index 2c39753..c4375c8 100644
> --- a/hw/display/xenfb.c
> +++ b/hw/display/xenfb.c
> @@ -54,6 +54,7 @@
> struct common {
> struct XenDevice xendev; /* must be first */
> void *page;
> + int page_gref;
> QemuConsole *con;
> };
>
> @@ -96,22 +97,36 @@ static int common_bind(struct common *c)
> {
> uint64_t mfn;
>
> - if (xenstore_read_fe_uint64(&c->xendev, "page-ref", &mfn) == -1)
> - return -1;
> - assert(mfn == (xen_pfn_t)mfn);
> -
> if (xenstore_read_fe_int(&c->xendev, "event-channel",
> &c->xendev.remote_port) == -1)
> return -1;
>
> - c->page = xc_map_foreign_range(xen_xc, c->xendev.dom,
> - XC_PAGE_SIZE,
> - PROT_READ | PROT_WRITE, mfn);
> + if (xenstore_read_fe_uint64(&c->xendev, "page-ref", &mfn) == -1) {
> + if (xenstore_read_fe_int(&c->xendev, "page-gref", &c->page_gref) ==
> -1) {
> + return -1;
> + }
> + c->page = xc_gnttab_map_grant_ref(c->xendev.gnttabdev,
> + c->xendev.dom,
> + c->page_gref,
> + PROT_READ | PROT_WRITE);
> + } else {
> + assert(mfn == (xen_pfn_t)mfn);
> +
> + c->page = xc_map_foreign_range(xen_xc, c->xendev.dom,
> + XC_PAGE_SIZE,
> + PROT_READ | PROT_WRITE, mfn);
> + }
This is an extension of the protocol. It should be documented somewhere.
At least in the commit message and somewhere under docs/misc or
xen/include/public/io/fbif.h.
> if (c->page == NULL)
> return -1;
>
> xen_be_bind_evtchn(&c->xendev);
> - xen_be_printf(&c->xendev, 1, "ring mfn %"PRIx64", remote-port %d,
> local-port %d\n",
> - mfn, c->xendev.remote_port, c->xendev.local_port);
> +
> + if (c->page_gref) {
> + xen_be_printf(&c->xendev, 1, "ring gref %d, remote-port %d,
> local-port %d\n",
> + c->page_gref, c->xendev.remote_port,
> c->xendev.local_port);
> + } else {
> + xen_be_printf(&c->xendev, 1, "ring mfn %"PRIx64", remote-port %d,
> local-port %d\n",
> + mfn, c->xendev.remote_port, c->xendev.local_port);
> + }
>
> return 0;
> }
> @@ -120,8 +135,13 @@ static void common_unbind(struct common *c)
> {
> xen_be_unbind_evtchn(&c->xendev);
> if (c->page) {
> - munmap(c->page, XC_PAGE_SIZE);
> + if (c->page_gref) {
> + xc_gnttab_munmap(c->xendev.gnttabdev, c->page, 1);
> + } else {
> + munmap(c->page, XC_PAGE_SIZE);
> + }
> c->page = NULL;
> + c->page_gref = 0;
> }
> }
>
> @@ -954,6 +974,7 @@ static void fb_event(struct XenDevice *xendev)
>
> struct XenDevOps xen_kbdmouse_ops = {
> .size = sizeof(struct XenInput),
> + .flags = DEVOPS_FLAG_NEED_GNTDEV,
> .init = input_init,
> .initialise = input_initialise,
> .connected = input_connected,
> --
> 2.1.0
>