[PATCH v2] tools: probe for existence of qemu-xen stderr trace backend.

[PATCH v2] tools: probe for existence of qemu-xen stderr trace backend.

[Ian Campbell]

QEMU upstream commit ed7f5f1d8db0 ("trace: convert stderr backend to
log") renamed the "stderr" trace backend to "log", which breaks the
xen build when pointed at a QEMU tree after that point:

./configure of QEMU fail with:
"ERROR: invalid trace backends
        Please choose supported trace backends."

Upstream also changed, in baf86d6b3ca0 ("trace: switch default backend
to "log""), to use "log" as the default backend (previously it was
"nop").

Use ./scripts/tracetool.py to check for the presence of the stderr
backend and if it is present then explicitly enable it. If the stderr
backend is not present then assume a newer QEMU which defaults to
"log" and simply accept that default (there is a 1 commit window
upstream where this would result in no trace backend being enabled).

The check is done using the older (deprecated?) --check-backend/--backend
variant of the tracetool.py options rather than the new plural
versions since the singular was supported even by very old versions of
QEMU.  New QEMU has compatibility code but if/when that is removed we
will still do the right thing i.e. no explict configuiration resulting
in the upstream default (currently "log").

If the explicit selection of the "stderr" backend is required then it
is now done unconditionally (not depending on debug=y), which is
simpler to arrange here but also matches the newer upstream's default
to "log" which is not conditional on debug being enabled either.

Tested with current qemu-xen-unstable (e9d8252) and current QEMU
upstream master (88c73d1), both out of tree via
QEMU_UPSTREAM_URL=/path/to/qemu-xen.git.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Paul Durrant <paul.durrant@citrix.com>
Cc: Anthony PERARD <anthony.perard@citrix.com>
---
v2: Just probe for stderr, otherwise assume the new upstream default
    of log is what we will get anyway. Substantially rewrite commit
    message.
---
 tools/Makefile | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/Makefile b/tools/Makefile
index cb8652c..3f45fb9 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -228,7 +228,7 @@ qemu-xen-dir-force-update: qemu-xen-dir-find
 	fi
 
 ifeq ($(debug),y)
-QEMU_XEN_ENABLE_DEBUG := --enable-debug --enable-trace-backend=stderr
+QEMU_XEN_ENABLE_DEBUG := --enable-debug
 else
 QEMU_XEN_ENABLE_DEBUG :=
 endif
@@ -240,8 +240,14 @@ subdir-all-qemu-xen-dir: qemu-xen-dir-find
 		source=.; \
 	fi; \
 	cd qemu-xen-dir; \
+	if $$source/scripts/tracetool.py --check-backend --backend stderr ; then \
+		enable_trace_backend='--enable-trace-backend=stderr'; \
+	else \
+		enable_trace_backend='' ; \
+	fi ; \
 	$$source/configure --enable-xen --target-list=i386-softmmu \
 		$(QEMU_XEN_ENABLE_DEBUG) \
+		$$enable_trace_backend \
 		--prefix=$(LIBEXEC) \
 		--libdir=$(LIBEXEC_LIB) \
 		--includedir=$(LIBEXEC_INC) \
-- 
2.1.4

Re: [PATCH v2] tools: probe for existence of qemu-xen stderr trace backend.

[Paul Durrant]

> -----Original Message-----
> From: Ian Campbell [mailto:ian.campbell@citrix.com]
> Sent: 11 February 2016 12:11
> To: Ian Jackson; Wei Liu; xen-devel@lists.xen.org; Stefano Stabellini
> Cc: Ian Campbell; Paul Durrant; Anthony Perard
> Subject: [PATCH v2] tools: probe for existence of qemu-xen stderr trace
> backend.
> 
> QEMU upstream commit ed7f5f1d8db0 ("trace: convert stderr backend to
> log") renamed the "stderr" trace backend to "log", which breaks the
> xen build when pointed at a QEMU tree after that point:
> 
> ./configure of QEMU fail with:
> "ERROR: invalid trace backends
>         Please choose supported trace backends."
> 
> Upstream also changed, in baf86d6b3ca0 ("trace: switch default backend
> to "log""), to use "log" as the default backend (previously it was
> "nop").
> 
> Use ./scripts/tracetool.py to check for the presence of the stderr
> backend and if it is present then explicitly enable it. If the stderr
> backend is not present then assume a newer QEMU which defaults to
> "log" and simply accept that default (there is a 1 commit window
> upstream where this would result in no trace backend being enabled).
> 
> The check is done using the older (deprecated?) --check-backend/--backend
> variant of the tracetool.py options rather than the new plural
> versions since the singular was supported even by very old versions of
> QEMU.  New QEMU has compatibility code but if/when that is removed we
> will still do the right thing i.e. no explict configuiration resulting
> in the upstream default (currently "log").
> 
> If the explicit selection of the "stderr" backend is required then it
> is now done unconditionally (not depending on debug=y), which is
> simpler to arrange here but also matches the newer upstream's default
> to "log" which is not conditional on debug being enabled either.
> 
> Tested with current qemu-xen-unstable (e9d8252) and current QEMU
> upstream master (88c73d1), both out of tree via
> QEMU_UPSTREAM_URL=/path/to/qemu-xen.git.
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: Paul Durrant <paul.durrant@citrix.com>

LGTM.

Reviewed-by: Paul Durrant <paul.durrant@citrix.com>

> Cc: Anthony PERARD <anthony.perard@citrix.com>
> ---
> v2: Just probe for stderr, otherwise assume the new upstream default
>     of log is what we will get anyway. Substantially rewrite commit
>     message.
> ---
>  tools/Makefile | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/Makefile b/tools/Makefile
> index cb8652c..3f45fb9 100644
> --- a/tools/Makefile
> +++ b/tools/Makefile
> @@ -228,7 +228,7 @@ qemu-xen-dir-force-update: qemu-xen-dir-find
>  	fi
> 
>  ifeq ($(debug),y)
> -QEMU_XEN_ENABLE_DEBUG := --enable-debug --enable-trace-
> backend=stderr
> +QEMU_XEN_ENABLE_DEBUG := --enable-debug
>  else
>  QEMU_XEN_ENABLE_DEBUG :=
>  endif
> @@ -240,8 +240,14 @@ subdir-all-qemu-xen-dir: qemu-xen-dir-find
>  		source=.; \
>  	fi; \
>  	cd qemu-xen-dir; \
> +	if $$source/scripts/tracetool.py --check-backend --backend stderr ;
> then \
> +		enable_trace_backend='--enable-trace-backend=stderr'; \
> +	else \
> +		enable_trace_backend='' ; \
> +	fi ; \
>  	$$source/configure --enable-xen --target-list=i386-softmmu \
>  		$(QEMU_XEN_ENABLE_DEBUG) \
> +		$$enable_trace_backend \
>  		--prefix=$(LIBEXEC) \
>  		--libdir=$(LIBEXEC_LIB) \
>  		--includedir=$(LIBEXEC_INC) \
> --
> 2.1.4

Re: [PATCH v2] tools: probe for existence of qemu-xen stderr trace backend.

[Stefano Stabellini]

On Thu, 11 Feb 2016, Ian Campbell wrote:
> QEMU upstream commit ed7f5f1d8db0 ("trace: convert stderr backend to
> log") renamed the "stderr" trace backend to "log", which breaks the
> xen build when pointed at a QEMU tree after that point:
> 
> ./configure of QEMU fail with:
> "ERROR: invalid trace backends
>         Please choose supported trace backends."
> 
> Upstream also changed, in baf86d6b3ca0 ("trace: switch default backend
> to "log""), to use "log" as the default backend (previously it was
> "nop").
> 
> Use ./scripts/tracetool.py to check for the presence of the stderr
> backend and if it is present then explicitly enable it. If the stderr
> backend is not present then assume a newer QEMU which defaults to
> "log" and simply accept that default (there is a 1 commit window
> upstream where this would result in no trace backend being enabled).
> 
> The check is done using the older (deprecated?) --check-backend/--backend
> variant of the tracetool.py options rather than the new plural
> versions since the singular was supported even by very old versions of
> QEMU.  New QEMU has compatibility code but if/when that is removed we
> will still do the right thing i.e. no explict configuiration resulting
> in the upstream default (currently "log").
> 
> If the explicit selection of the "stderr" backend is required then it
> is now done unconditionally (not depending on debug=y), which is
> simpler to arrange here but also matches the newer upstream's default
> to "log" which is not conditional on debug being enabled either.
> 
> Tested with current qemu-xen-unstable (e9d8252) and current QEMU
> upstream master (88c73d1), both out of tree via
> QEMU_UPSTREAM_URL=/path/to/qemu-xen.git.
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: Paul Durrant <paul.durrant@citrix.com>
> Cc: Anthony PERARD <anthony.perard@citrix.com>

Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>


> v2: Just probe for stderr, otherwise assume the new upstream default
>     of log is what we will get anyway. Substantially rewrite commit
>     message.
> ---
>  tools/Makefile | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/Makefile b/tools/Makefile
> index cb8652c..3f45fb9 100644
> --- a/tools/Makefile
> +++ b/tools/Makefile
> @@ -228,7 +228,7 @@ qemu-xen-dir-force-update: qemu-xen-dir-find
>  	fi
>  
>  ifeq ($(debug),y)
> -QEMU_XEN_ENABLE_DEBUG := --enable-debug --enable-trace-backend=stderr
> +QEMU_XEN_ENABLE_DEBUG := --enable-debug
>  else
>  QEMU_XEN_ENABLE_DEBUG :=
>  endif
> @@ -240,8 +240,14 @@ subdir-all-qemu-xen-dir: qemu-xen-dir-find
>  		source=.; \
>  	fi; \
>  	cd qemu-xen-dir; \
> +	if $$source/scripts/tracetool.py --check-backend --backend stderr ; then \
> +		enable_trace_backend='--enable-trace-backend=stderr'; \
> +	else \
> +		enable_trace_backend='' ; \
> +	fi ; \
>  	$$source/configure --enable-xen --target-list=i386-softmmu \
>  		$(QEMU_XEN_ENABLE_DEBUG) \
> +		$$enable_trace_backend \
>  		--prefix=$(LIBEXEC) \
>  		--libdir=$(LIBEXEC_LIB) \
>  		--includedir=$(LIBEXEC_INC) \
> -- 
> 2.1.4
> 

Re: [PATCH v2] tools: probe for existence of qemu-xen stderr trace backend.

[Wei Liu]

On Thu, Feb 11, 2016 at 12:11:21PM +0000, Ian Campbell wrote:
> QEMU upstream commit ed7f5f1d8db0 ("trace: convert stderr backend to
> log") renamed the "stderr" trace backend to "log", which breaks the
> xen build when pointed at a QEMU tree after that point:
> 
> ./configure of QEMU fail with:
> "ERROR: invalid trace backends
>         Please choose supported trace backends."
> 
> Upstream also changed, in baf86d6b3ca0 ("trace: switch default backend
> to "log""), to use "log" as the default backend (previously it was
> "nop").
> 
> Use ./scripts/tracetool.py to check for the presence of the stderr
> backend and if it is present then explicitly enable it. If the stderr
> backend is not present then assume a newer QEMU which defaults to
> "log" and simply accept that default (there is a 1 commit window
> upstream where this would result in no trace backend being enabled).
> 
> The check is done using the older (deprecated?) --check-backend/--backend
> variant of the tracetool.py options rather than the new plural
> versions since the singular was supported even by very old versions of
> QEMU.  New QEMU has compatibility code but if/when that is removed we
> will still do the right thing i.e. no explict configuiration resulting
> in the upstream default (currently "log").
> 
> If the explicit selection of the "stderr" backend is required then it
> is now done unconditionally (not depending on debug=y), which is
> simpler to arrange here but also matches the newer upstream's default
> to "log" which is not conditional on debug being enabled either.
> 
> Tested with current qemu-xen-unstable (e9d8252) and current QEMU
> upstream master (88c73d1), both out of tree via
> QEMU_UPSTREAM_URL=/path/to/qemu-xen.git.
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: Paul Durrant <paul.durrant@citrix.com>
> Cc: Anthony PERARD <anthony.perard@citrix.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

> ---
> v2: Just probe for stderr, otherwise assume the new upstream default
>     of log is what we will get anyway. Substantially rewrite commit
>     message.
> ---
>  tools/Makefile | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/Makefile b/tools/Makefile
> index cb8652c..3f45fb9 100644
> --- a/tools/Makefile
> +++ b/tools/Makefile
> @@ -228,7 +228,7 @@ qemu-xen-dir-force-update: qemu-xen-dir-find
>  	fi
>  
>  ifeq ($(debug),y)
> -QEMU_XEN_ENABLE_DEBUG := --enable-debug --enable-trace-backend=stderr
> +QEMU_XEN_ENABLE_DEBUG := --enable-debug
>  else
>  QEMU_XEN_ENABLE_DEBUG :=
>  endif
> @@ -240,8 +240,14 @@ subdir-all-qemu-xen-dir: qemu-xen-dir-find
>  		source=.; \
>  	fi; \
>  	cd qemu-xen-dir; \
> +	if $$source/scripts/tracetool.py --check-backend --backend stderr ; then \
> +		enable_trace_backend='--enable-trace-backend=stderr'; \
> +	else \
> +		enable_trace_backend='' ; \
> +	fi ; \
>  	$$source/configure --enable-xen --target-list=i386-softmmu \
>  		$(QEMU_XEN_ENABLE_DEBUG) \
> +		$$enable_trace_backend \
>  		--prefix=$(LIBEXEC) \
>  		--libdir=$(LIBEXEC_LIB) \
>  		--includedir=$(LIBEXEC_INC) \
> -- 
> 2.1.4
> 

Re: [PATCH v2] tools: probe for existence of qemu-xen stderr trace backend.

[Ian Campbell]

On Thu, 2016-02-11 at 16:30 +0000, Wei Liu wrote:
> On Thu, Feb 11, 2016 at 12:11:21PM +0000, Ian Campbell wrote:
> > QEMU upstream commit ed7f5f1d8db0 ("trace: convert stderr backend to
> > log") renamed the "stderr" trace backend to "log", which breaks the
> > xen build when pointed at a QEMU tree after that point:
> > 
> > ./configure of QEMU fail with:
> > "ERROR: invalid trace backends
> >         Please choose supported trace backends."
> > 
> > Upstream also changed, in baf86d6b3ca0 ("trace: switch default backend
> > to "log""), to use "log" as the default backend (previously it was
> > "nop").
> > 
> > Use ./scripts/tracetool.py to check for the presence of the stderr
> > backend and if it is present then explicitly enable it. If the stderr
> > backend is not present then assume a newer QEMU which defaults to
> > "log" and simply accept that default (there is a 1 commit window
> > upstream where this would result in no trace backend being enabled).
> > 
> > The check is done using the older (deprecated?) --check-backend/
> > --backend
> > variant of the tracetool.py options rather than the new plural
> > versions since the singular was supported even by very old versions of
> > QEMU.  New QEMU has compatibility code but if/when that is removed we
> > will still do the right thing i.e. no explict configuiration resulting
> > in the upstream default (currently "log").
> > 
> > If the explicit selection of the "stderr" backend is required then it
> > is now done unconditionally (not depending on debug=y), which is
> > simpler to arrange here but also matches the newer upstream's default
> > to "log" which is not conditional on debug being enabled either.
> > 
> > Tested with current qemu-xen-unstable (e9d8252) and current QEMU
> > upstream master (88c73d1), both out of tree via
> > QEMU_UPSTREAM_URL=/path/to/qemu-xen.git.
> > 
> > Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> > Cc: Paul Durrant <paul.durrant@citrix.com>
> > Cc: Anthony PERARD <anthony.perard@citrix.com>
> 
> Acked-by: Wei Liu <wei.liu2@citrix.com>

Thanks, applied.


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
http://lists.xen.org/xen-devel