hvmloader: Remove minimum size for BARs to relocate to 64-bit space

Allow devices with BARs less than 512MiB to be relocated to high
memory.

This will only be invoked if there is not enough low MMIO space to map
the device, and will be done preferentially to large devices first; so
in all likelihood only large devices will be remapped anyway.

This is needed to work-around the issue of qemu-xen not being able to
handle moving guest memory around to resize the MMIO hole.  The
default MMIO hole size is less than 256MiB.

v3:
 - Fixed minor style issue

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
CC: Ian Campbell <ian.campbell@citrix.com>
CC: Hanweidong <hanweidong@huawei.com>
CC: Keir Fraser <keir@xen.org>

2 files changed, 2 insertions, 4 deletions

diff --git a/tools/firmware/hvmloader/config.h b/tools/firmware/hvmloader/config.h
index 8143d6f11b..6641197b09 100644
--- a/tools/firmware/hvmloader/config.h
+++ b/tools/firmware/hvmloader/config.h
@@ -55,7 +55,6 @@ extern struct bios_config ovmf_config;
 /* MMIO hole: Hardcoded defaults, which can be dynamically expanded. */
 #define PCI_MEM_START       0xf0000000
 #define PCI_MEM_END         0xfc000000
-#define PCI_MIN_BIG_BAR_SIZE          0x20000000
 
 extern unsigned long pci_mem_start, pci_mem_end;
 
diff --git a/tools/firmware/hvmloader/pci.c b/tools/firmware/hvmloader/pci.c
index 68d4e44028..9253b0b4c6 100644
--- a/tools/firmware/hvmloader/pci.c
+++ b/tools/firmware/hvmloader/pci.c
@@ -295,9 +295,8 @@ void pci_setup(void)
         if ( (bar_data & PCI_BASE_ADDRESS_SPACE) ==
              PCI_BASE_ADDRESS_SPACE_MEMORY )
         {
-            /* Mapping high memory if PCI deivce is 64 bits bar and the bar size
-               is larger than 512M */
-            if (using_64bar && (bar_sz > PCI_MIN_BIG_BAR_SIZE)) {
+            /* Mapping high memory if PCI device is 64 bits bar */
+            if ( using_64bar ) {
                 if ( high_mem_resource.base & (bar_sz - 1) )
                     high_mem_resource.base = high_mem_resource.base - 
                         (high_mem_resource.base & (bar_sz - 1)) + bar_sz;