Re: [PATCH] docs:remove cxl3 device size

[Jonathan Cameron via <qemu-devel@nongnu.org>]

On Wed,  5 Apr 2023 15:57:38 +0530
Raghu H <raghuhack78@gmail.com> wrote:
Hi Raghu,

Thanks for tidying this up! (and reporting it in the first place)
A few minor comments for v2.


A better title might be
docs/cxl: Remove incorrect CXL type 3 size parameter.

> cxl device typ3 size is read from the memory backend device, removing the

cxl-type3 memory size is read directly from the provided memory backed end device.
Remove non existent size option.

> size option specified in cxl sample command.
> 
> Updating sample command to reflect target architecture as x86_64.

There are two changes in here.  Please split it into two patches and
add a minimal cover letter (mostly as it gives a place for people to
respond to both of them with tags etc).

> 
> Signed-off-by: Raghu H <raghuhack78@gmail.com>
> ---
>  docs/system/devices/cxl.rst | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/docs/system/devices/cxl.rst b/docs/system/devices/cxl.rst
> index f25783a4ec..b228146cec 100644
> --- a/docs/system/devices/cxl.rst
> +++ b/docs/system/devices/cxl.rst
> @@ -302,7 +302,7 @@ Example command lines
>  ---------------------
>  A very simple setup with just one directly attached CXL Type 3 device::
>  
> -  qemu-system-aarch64 -M virt,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max \
> +  qemu-system-x86_64 -m 4G,slots=8,maxmem=8G -smp 4 -machine type=q35,accel=kvm,nvdimm=on,cxl=on -enable-kvm \

Minimize the change (and definitely don't tell people to use kvm as that's broken for
some usecases - instructions in CXL memory).

+ qemu-system-x86_64 -M q35,cxl=on -m 4G,maxmem=8G,slots=8 \
is probably the right combination (I tidied up the g / G mix whilst touching the line.

>    ...
>    -object memory-backend-file,id=cxl-mem1,share=on,mem-path=/tmp/cxltest.raw,size=256M \
>    -object memory-backend-file,id=cxl-lsa1,share=on,mem-path=/tmp/lsa.raw,size=256M \
> @@ -315,7 +315,7 @@ A setup suitable for 4 way interleave. Only one fixed window provided, to enable
>  interleave across 2 CXL host bridges.  Each host bridge has 2 CXL Root Ports, with
>  the CXL Type3 device directly attached (no switches).::
>  
> -  qemu-system-aarch64 -M virt,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max \
> +  qemu-system-x86_64 -m 4G,slots=8,maxmem=8G -smp 4 -machine type=q35,accel=kvm,nvdimm=on,cxl=on -enable-kvm \
>    ...
>    -object memory-backend-file,id=cxl-mem1,share=on,mem-path=/tmp/cxltest.raw,size=256M \
>    -object memory-backend-file,id=cxl-mem2,share=on,mem-path=/tmp/cxltest2.raw,size=256M \
> @@ -339,7 +339,7 @@ the CXL Type3 device directly attached (no switches).::
>  
>  An example of 4 devices below a switch suitable for 1, 2 or 4 way interleave::
>  
> -  qemu-system-aarch64 -M virt,gic-version=3,cxl=on -m 4g,maxmem=8G,slots=8 -cpu max \
> +  qemu-system-x86_64 -m 4G,slots=8,maxmem=8G -smp 4 -machine type=q35,accel=kvm,nvdimm=on,cxl=on -enable-kvm \
>    ...
>    -object memory-backend-file,id=cxl-mem0,share=on,mem-path=/tmp/cxltest.raw,size=256M \
>    -object memory-backend-file,id=cxl-mem1,share=on,mem-path=/tmp/cxltest1.raw,size=256M \
> @@ -354,13 +354,13 @@ An example of 4 devices below a switch suitable for 1, 2 or 4 way interleave::
>    -device cxl-rp,port=1,bus=cxl.1,id=root_port1,chassis=0,slot=1 \
>    -device cxl-upstream,bus=root_port0,id=us0 \
>    -device cxl-downstream,port=0,bus=us0,id=swport0,chassis=0,slot=4 \
> -  -device cxl-type3,bus=swport0,memdev=cxl-mem0,lsa=cxl-lsa0,id=cxl-pmem0,size=256M \
> +  -device cxl-type3,bus=swport0,memdev=cxl-mem0,lsa=cxl-lsa0,id=cxl-pmem0 \
>    -device cxl-downstream,port=1,bus=us0,id=swport1,chassis=0,slot=5 \
> -  -device cxl-type3,bus=swport1,memdev=cxl-mem1,lsa=cxl-lsa1,id=cxl-pmem1,size=256M \
> +  -device cxl-type3,bus=swport1,memdev=cxl-mem1,lsa=cxl-lsa1,id=cxl-pmem1 \
>    -device cxl-downstream,port=2,bus=us0,id=swport2,chassis=0,slot=6 \
> -  -device cxl-type3,bus=swport2,memdev=cxl-mem2,lsa=cxl-lsa2,id=cxl-pmem2,size=256M \
> +  -device cxl-type3,bus=swport2,memdev=cxl-mem2,lsa=cxl-lsa2,id=cxl-pmem2 \
>    -device cxl-downstream,port=3,bus=us0,id=swport3,chassis=0,slot=7 \
> -  -device cxl-type3,bus=swport3,memdev=cxl-mem3,lsa=cxl-lsa3,id=cxl-pmem3,size=256M \
> +  -device cxl-type3,bus=swport3,memdev=cxl-mem3,lsa=cxl-lsa3,id=cxl-pmem3 \
>    -M cxl-fmw.0.targets.0=cxl.1,cxl-fmw.0.size=4G,cxl-fmw.0.interleave-granularity=4k
>  
>  Kernel Configuration Options