Re: [Xen-devel] [PATCH v2 3/5] hvmloader: Remove minimum size for BARs to relocate to 64-bit space

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Tue, Jun 18, 2013 at 05:46:22PM +0100, George Dunlap wrote:
> 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.
> 
> Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> CC: Ian Jackson <ian.jackson@xxxxxxxxxx>
> CC: Ian Campbell <ian.campbell@xxxxxxxxxx>
> CC: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
> CC: Hanweidong <hanweidong@xxxxxxxxxx>
> ---
>  tools/firmware/hvmloader/config.h |    1 -
>  tools/firmware/hvmloader/pci.c    |    5 ++---
>  2 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/tools/firmware/hvmloader/config.h 
> b/tools/firmware/hvmloader/config.h
> index 8143d6f..6641197 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 7f306a1..a483b02 100644
> --- a/tools/firmware/hvmloader/pci.c
> +++ b/tools/firmware/hvmloader/pci.c
> @@ -265,9 +265,8 @@ 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) {

I think the original had style problem, if you look at other occurrences
for 'if', it should be

  if ( condition )
      statement;


Wei.

>                  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;
> -- 
> 1.7.9.5
> 
> 
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> http://lists.xen.org/xen-devel

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