haraldwolff/qemu-patch-raspberry4
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xenfb: map framebuffer read-only and handle unmap errors

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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: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
This commit is contained in:
Stefano Stabellini 2014-01-17 15:28:18 +00:00
parent 1cf892ca26
commit 0193c62c94
1 changed files with 6 additions and 1 deletions
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7
hw/display/xenfb.c
View file

@ -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;