Re: [PATCH v2] tools: hv: Fix cross-compilation

[Aditya Garg <gargaditya@linux.microsoft.com>]

On 07-04-2026 17:50, Aditya Garg wrote:
> Use the native ARCH only in case it is not set, this will allow the
> cross-compilation where ARCH is explicitly set.
> 
> Additionally, simplify the check for ARCH so that fcopy daemon is built
> only for x86_64.
> 
> Fixes: 82b0945ce2c2 ("tools: hv: Add new fcopy application based on uio driver")
> Reported-by: Adrian Vladu <avladu@cloudbasesolutions.com>
> Closes: https://lore.kernel.org/linux-hyperv/PR3PR09MB54119DB2FD76977C62D8DD6AB04D2@PR3PR09MB5411.eurprd09.prod.outlook.com/
> Co-developed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
> Signed-off-by: Aditya Garg <gargaditya@linux.microsoft.com>
> Reviewed-by: Roman Kisel <romank@linux.microsoft.com>
> ---
> Changes since v1:
>      - Dropped the info target printing CC, LD and ARCH
> 
> v1: https://lore.kernel.org/all/1733992114-7305-1-git-send-email-ssengar@linux.microsoft.com/
> ---
>   tools/hv/Makefile | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/hv/Makefile b/tools/hv/Makefile
> index 34ffcec264ab..e377caf89fb6 100644
> --- a/tools/hv/Makefile
> +++ b/tools/hv/Makefile
> @@ -2,7 +2,7 @@
>   # Makefile for Hyper-V tools
>   include ../scripts/Makefile.include
>   
> -ARCH := $(shell uname -m 2>/dev/null)
> +ARCH ?= $(shell uname -m 2>/dev/null)
>   sbindir ?= /usr/sbin
>   libexecdir ?= /usr/libexec
>   sharedstatedir ?= /var/lib
> @@ -20,7 +20,7 @@ override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
>   override CFLAGS += -Wno-address-of-packed-member
>   
>   ALL_TARGETS := hv_kvp_daemon hv_vss_daemon
> -ifneq ($(ARCH), aarch64)
> +ifeq ($(ARCH), x86_64)
>   ALL_TARGETS += hv_fcopy_uio_daemon
>   endif
>   ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))

Sashiko AI review flagged an issue, I tested it and confirmed.
When building via make tools/hv from the top-level kernel directory,
scripts/subarch.include normalizes x86_64 to x86, and since ARCH is
exported, the ?= assignment in tools/hv/Makefile preserves the
normalized value, causing ifeq ($(ARCH), x86_64) to be false and
hv_fcopy_uio_daemon to be silently excluded.

I'll change this to include x86 as well in v3.

Regards,
Aditya