drivers:hv: Record MMIO range in use by frame buffer
Later in the boot sequence, we need to figure out which memory
ranges can be given out to various paravirtual drivers. The
hyperv_fb driver should, ideally, be placed right on top of
the frame buffer, without some other device getting plopped on
top of this range in the meantime. Recording this now allows
that to be guaranteed.
Signed-off-by: Jake Oshins <jakeo@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index dfc6149..eaa5c3b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -41,6 +41,7 @@
#include <linux/ptrace.h>
#include <linux/screen_info.h>
#include <linux/kdebug.h>
+#include <linux/efi.h>
#include "hyperv_vmbus.h"
static struct acpi_device *hv_acpi_dev;
@@ -101,6 +102,8 @@
.notifier_call = hyperv_panic_event,
};
+static const char *fb_mmio_name = "fb_range";
+static struct resource *fb_mmio;
struct resource *hyperv_mmio;
DEFINE_SEMAPHORE(hyperv_mmio_lock);
@@ -1091,6 +1094,12 @@
struct resource *next_res;
if (hyperv_mmio) {
+ if (fb_mmio) {
+ __release_region(hyperv_mmio, fb_mmio->start,
+ resource_size(fb_mmio));
+ fb_mmio = NULL;
+ }
+
for (cur_res = hyperv_mmio; cur_res; cur_res = next_res) {
next_res = cur_res->sibling;
kfree(cur_res);
@@ -1100,6 +1109,30 @@
return 0;
}
+static void vmbus_reserve_fb(void)
+{
+ int size;
+ /*
+ * Make a claim for the frame buffer in the resource tree under the
+ * first node, which will be the one below 4GB. The length seems to
+ * be underreported, particularly in a Generation 1 VM. So start out
+ * reserving a larger area and make it smaller until it succeeds.
+ */
+
+ if (screen_info.lfb_base) {
+ if (efi_enabled(EFI_BOOT))
+ size = max_t(__u32, screen_info.lfb_size, 0x800000);
+ else
+ size = max_t(__u32, screen_info.lfb_size, 0x4000000);
+
+ for (; !fb_mmio && (size >= 0x100000); size >>= 1) {
+ fb_mmio = __request_region(hyperv_mmio,
+ screen_info.lfb_base, size,
+ fb_mmio_name, 0);
+ }
+ }
+}
+
/**
* vmbus_allocate_mmio() - Pick a memory-mapped I/O range.
* @new: If successful, supplied a pointer to the
@@ -1261,8 +1294,10 @@
if (ACPI_FAILURE(result))
continue;
- if (hyperv_mmio)
+ if (hyperv_mmio) {
+ vmbus_reserve_fb();
break;
+ }
}
ret_val = 0;