Re: [PATCH] OvmfPkg/XenHypercallLib: enable virt extensions for ARM

[Laszlo Ersek <lersek@redhat.com>]

On 11/16/17 17:56, Ard Biesheuvel wrote:
> XenHypercallLib uses the 'hvc' instruction, which is not implemented
> on all ARMv7 CPUs, and so we need to explicitly specify a CPU that
> has the virtualization extensions.
> 
> This override used to be set at the platform level, but this was removed
> in commit 0d36a219c7bdbb27d775b50837823b2a9928147c
> ('ArmPlatformPkg/PL031RealTimeClockLib: drop ArmPlatformSysConfigLib
> reference), under the assumption that all users of the 'hvc' instruction
> had already been fixed.
> 
> So fix this for GNU binutils by adding the 'virt' arch extension
> directive, and for RVCT by setting the --cpu command line option to a
> CPU that is virt capable.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S     | 2 ++
>  OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf | 3 +++
>  2 files changed, 5 insertions(+)
> 
> diff --git a/OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S b/OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S
> index c12c8658b729..0adf65840a2f 100644
> --- a/OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S
> +++ b/OvmfPkg/Library/XenHypercallLib/Arm/Hypercall.S
> @@ -16,6 +16,8 @@
>  #include <IndustryStandard/Xen/arch-arm/xen.h>
>  
>    .text
> +  .arch_extension virt
> +
>  GCC_ASM_EXPORT(XenHypercall2)
>  
>  ASM_PFX(XenHypercall2):
> diff --git a/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf b/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
> index f4503a4b01f4..d268e540feca 100644
> --- a/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
> +++ b/OvmfPkg/Library/XenHypercallLib/XenHypercallLib.inf
> @@ -64,3 +64,6 @@ [LibraryClasses.IA32, LibraryClasses.X64]
>  
>  [Guids.IA32, Guids.X64]
>    gEfiXenInfoGuid
> +
> +[BuildOptions.ARM]
> +  RVCT:*_*_ARM_PLATFORM_FLAGS == --cpu Cortex-A15
> 

Acked-by: Laszlo Ersek <lersek@redhat.com>