From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@linaro.org>

Date: Mon, 28 Nov 2022 21:27:38 +0100

Subject: hw/display/qxl: Document qxl_phys2virt()

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Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Message-Id: <20221128202741.4945-3-philmd@linaro.org>

(cherry picked from commit b1901de83a9456cde26fc755f71ca2b7b3ef50fc)

Resolves: bsc#1205808

Fixes: CVE-2022-4144

Signed-off-by: Dario Faggioli <dfaggioli@suse.com>

---

 hw/display/qxl.h | 19 +++++++++++++++++++

 1 file changed, 19 insertions(+)

diff --git a/hw/display/qxl.h b/hw/display/qxl.h

index e74de9579df3db6e3b6924b1a8c2..78b3a6c9ba8e3a598d6553867a6c 100644

--- a/hw/display/qxl.h

+++ b/hw/display/qxl.h

@@ -147,6 +147,25 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL)

 #define QXL_DEFAULT_REVISION (QXL_REVISION_STABLE_V12 + 1)

 /* qxl.c */

+/**

+ * qxl_phys2virt: Get a pointer within a PCI VRAM memory region.

+ *

+ * @qxl: QXL device

+ * @phys: physical offset of buffer within the VRAM

+ * @group_id: memory slot group

+ *

+ * Returns a host pointer to a buffer placed at offset @phys within the

+ * active slot @group_id of the PCI VGA RAM memory region associated with

+ * the @qxl device. If the slot is inactive, or the offset is out

+ * of the memory region, returns NULL.

+ *

+ * Use with care; by the time this function returns, the returned pointer is

+ * not protected by RCU anymore.  If the caller is not within an RCU critical

+ * section and does not hold the iothread lock, it must have other means of

+ * protecting the pointer, such as a reference to the region that includes

+ * the incoming ram_addr_t.

+ *

+ */

 void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL phys, int group_id);

 void qxl_set_guest_bug(PCIQXLDevice *qxl, const char *msg, ...)

     G_GNUC_PRINTF(2, 3);