xen/arm: Blacklist sun7i UARTs

These are in the same page as the UART which is used as the Xen console. We are
not currently smart enough to avoid passing them through to the guest,
accidentally giving the guest access to the Xen console UART.

we blacklist them all, if necessary in the future we can split the list into
two halves and make a per platform decision about which half should be
blacklisted on a given platform depending on which UART is wired up as the
console.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Julien Grall <julien.grall@linaro.org>

diff --git a/xen/arch/arm/platforms/sunxi.c b/xen/arch/arm/platforms/sunxi.c
index ab3b4a64fabd5aa5fcfa5f6736094d3b3d4cbfe7..b466518757e71ed56d8ae69c15796793385b70f0 100644 (file)
--- a/xen/arch/arm/platforms/sunxi.c
+++ b/xen/arch/arm/platforms/sunxi.c
@@ -24,8 +24,19 @@ static const char * const sunxi_dt_compat[] __initconst =
     NULL
 };
 
+static const struct dt_device_match sunxi_blacklist_dev[] __initconst =
+{
+    /*
+     * The UARTs share a page which runs the risk of mapping the Xen console
+     * UART to dom0, so don't map any of them.
+     */
+    DT_MATCH_COMPATIBLE("snps,dw-apb-uart"),
+    { /* sentinel */ },
+};
+
 PLATFORM_START(sunxi, "Allwinner A20")
     .compatible = sunxi_dt_compat,
+    .blacklist_dev = sunxi_blacklist_dev,
 PLATFORM_END
 
 /*