[kvmtool test PATCH 22/24] kvmtool: arm64: Add support for guest physical address size

Hi,

On 04/07/18 15:09, Will Deacon wrote:

On Fri, Jun 29, 2018 at 12:15:42PM +0100, Suzuki K Poulose wrote:

quoted

Add an option to specify the physical address size used by this
VM.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
  arm/aarch64/include/kvm/kvm-config-arch.h | 5 ++++-
  arm/include/arm-common/kvm-config-arch.h  | 1 +
  2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arm/aarch64/include/kvm/kvm-config-arch.h b/arm/aarch64/include/kvm/kvm-config-arch.h
index 04be43d..dabd22c 100644
--- a/arm/aarch64/include/kvm/kvm-config-arch.h
+++ b/arm/aarch64/include/kvm/kvm-config-arch.h

@@ -8,7 +8,10 @@
  			"Create PMUv3 device"),				\
  	OPT_U64('\0', "kaslr-seed", &(cfg)->kaslr_seed,			\
  			"Specify random seed for Kernel Address Space "	\
-			"Layout Randomization (KASLR)"),
+			"Layout Randomization (KASLR)"),		\
+	OPT_INTEGER('\0', "phys-shift", &(cfg)->phys_shift,		\
+			"Specify maximum physical address size (not "	\
+			"the amount of memory)"),

Given that this is a shift value, I think the help message could be more
informative. Something like:

	"Specify maximum number of bits in a guest physical address"

I think I'd actually leave out any mention of memory, because this does
actually have an effect on the amount of addressable memory in a way that I
don't think we want to describe in half of a usage message line :)

Is there any particular reasons to expose this option to the user?

I have recently sent a series to allow the user to specify the position
of the RAM [1]. With that series in mind, I think the user would not 
really need to specify the maximum physical shift. Instead we could 
automatically find it.

Cheers,

[1] 
http://archive.armlinux.org.uk/lurker/message/20180510.140428.1c295b5b.en.html

Will

-- 
Julien Grall