Commit 0193c62c authored by Stefano Stabellini's avatar Stefano Stabellini
Browse files

xenfb: map framebuffer read-only and handle unmap errors 



The framebuffer is needlessly mapped (PROT_READ | PROT_WRITE), map it
PROT_READ instead.

The framebuffer is unmapped by replacing the framebuffer pages with
anonymous shared memory, calling mmap. Check for return errors and print
a warning.

Signed-off-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
parent 1cf892ca

hw/display/xenfb.c

+6 −1
Original line number Diff line number Diff line
@@ -495,7 +495,7 @@ static int xenfb_map_fb(struct XenFB *xenfb) 
    munmap(map, n_fbdirs * XC_PAGE_SIZE);



    xenfb->pixels = xc_map_foreign_pages(xen_xc, xenfb->c.xendev.dom,

					 PROT_READ | PROT_WRITE, fbmfns, xenfb->fbpages);

            PROT_READ, fbmfns, xenfb->fbpages);

    if (xenfb->pixels == NULL)

	goto out;
@@ -903,6 +903,11 @@ static void fb_disconnect(struct XenDevice *xendev) 
    fb->pixels = mmap(fb->pixels, fb->fbpages * XC_PAGE_SIZE,

                      PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON,

                      -1, 0);

    if (fb->pixels == MAP_FAILED) {

        xen_be_printf(xendev, 0,

                "Couldn't replace the framebuffer with anonymous memory errno=%d\n",

                errno);

    }

    common_unbind(&fb->c);

    fb->feature_update = 0;

    fb->bug_trigger    = 0;