From: "Philippe Mathieu-Daudé" <philmd@redhat.com>
To: paul@xen.org, qemu-devel@nongnu.org
Cc: 'Peter Maydell' <peter.maydell@linaro.org>,
'Stefano Stabellini' <sstabellini@kernel.org>,
'Paul Durrant' <pdurrant@amazon.com>,
'Paolo Bonzini' <pbonzini@redhat.com>,
'Anthony Perard' <anthony.perard@citrix.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH-for-5.1 v2 1/1] accel/xen: Fix xen_enabled() behavior on target-agnostic objects
Date: Tue, 4 Aug 2020 10:34:42 +0200 [thread overview]
Message-ID: <56c70b44-2d5f-44fc-5d9a-535c3c5fca71@redhat.com> (raw)
In-Reply-To: <001201d66a34$e82ec070$b88c4150$@xen.org>
Hi Paul,
On 8/4/20 9:57 AM, Paul Durrant wrote:
>> -----Original Message-----
>> From: Philippe Mathieu-Daudé <philmd@redhat.com>
>> Sent: 04 August 2020 08:50
>> To: qemu-devel@nongnu.org
>> Cc: Peter Maydell <peter.maydell@linaro.org>; Anthony Perard <anthony.perard@citrix.com>; Paolo
>> Bonzini <pbonzini@redhat.com>; Stefano Stabellini <sstabellini@kernel.org>; xen-
>> devel@lists.xenproject.org; Paul Durrant <paul@xen.org>; Philippe Mathieu-Daudé <philmd@redhat.com>;
>> Paul Durrant <pdurrant@amazon.com>
>> Subject: [PATCH-for-5.1 v2 1/1] accel/xen: Fix xen_enabled() behavior on target-agnostic objects
>>
>> CONFIG_XEN is generated by configure and stored in "config-target.h",
>> which is (obviously) only include for target-specific objects.
>> This is a problem for target-agnostic objects as CONFIG_XEN is never
>> defined and xen_enabled() is always inlined as 'false'.
>>
>> Fix by following the KVM schema, defining CONFIG_XEN_IS_POSSIBLE
>> when we don't know to force the call of the non-inlined function,
>> returning the xen_allowed boolean.
>>
>> Fixes: da278d58a092 ("accel: Move Xen accelerator code under accel/xen/")
>> Reported-by: Paul Durrant <pdurrant@amazon.com>
>> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> ---
>> include/sysemu/xen.h | 18 ++++++++++++++----
>> accel/stubs/xen-stub.c | 2 ++
>> accel/xen/xen-all.c | 7 +------
>> 3 files changed, 17 insertions(+), 10 deletions(-)
>>
>> diff --git a/include/sysemu/xen.h b/include/sysemu/xen.h
>> index 1ca292715e..2c2c429ea8 100644
>> --- a/include/sysemu/xen.h
>> +++ b/include/sysemu/xen.h
>> @@ -8,9 +8,19 @@
>> #ifndef SYSEMU_XEN_H
>> #define SYSEMU_XEN_H
>>
>> -#ifdef CONFIG_XEN
>> +#ifdef NEED_CPU_H
>> +# ifdef CONFIG_XEN
>> +# define CONFIG_XEN_IS_POSSIBLE
>> +# endif
>> +#else
>> +# define CONFIG_XEN_IS_POSSIBLE
>> +#endif
>>
>> -bool xen_enabled(void);
>> +#ifdef CONFIG_XEN_IS_POSSIBLE
>> +
>> +extern bool xen_allowed;
>> +
>> +#define xen_enabled() (xen_allowed)
>
> Can this not move ahead of the #ifdef now (since xen_allowed is present in both xen-stub and xen-all)? I think this is what Peter was saying in his option '(2)'.
I think I respected Peter's option '(2)', following how KVM does, this
is the case with stub,
>
> Paul
>
>>
>> #ifndef CONFIG_USER_ONLY
>> void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t length);
>> @@ -18,7 +28,7 @@ void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
>> struct MemoryRegion *mr, Error **errp);
>> #endif
>>
>> -#else /* !CONFIG_XEN */
>> +#else /* !CONFIG_XEN_IS_POSSIBLE */
>>
>> #define xen_enabled() 0
^^^ here is the other case,
>> #ifndef CONFIG_USER_ONLY
>> @@ -33,6 +43,6 @@ static inline void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
>> }
>> #endif
>>
>> -#endif /* CONFIG_XEN */
>> +#endif /* CONFIG_XEN_IS_POSSIBLE */
>>
>> #endif
>> diff --git a/accel/stubs/xen-stub.c b/accel/stubs/xen-stub.c
>> index dcca4e678a..8ae658acff 100644
>> --- a/accel/stubs/xen-stub.c
>> +++ b/accel/stubs/xen-stub.c
>> @@ -9,6 +9,8 @@
>> #include "hw/xen/xen.h"
>> #include "qapi/qapi-commands-misc.h"
>>
>> +bool xen_allowed;
here is the stub,
>> +
>> void xenstore_store_pv_console_info(int i, Chardev *chr)
>> {
>> }
>> diff --git a/accel/xen/xen-all.c b/accel/xen/xen-all.c
>> index 0c24d4b191..60b971d0a8 100644
>> --- a/accel/xen/xen-all.c
>> +++ b/accel/xen/xen-all.c
>> @@ -32,12 +32,7 @@
>> do { } while (0)
>> #endif
>>
>> -static bool xen_allowed;
>> -
>> -bool xen_enabled(void)
>> -{
>> - return xen_allowed;
>> -}
>> +bool xen_allowed;
here is the real variable.
>>
>> xc_interface *xen_xc;
>> xenforeignmemory_handle *xen_fmem;
>> --
>> 2.21.3
>
>
next prev parent reply other threads:[~2020-08-04 8:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-04 7:49 [PATCH-for-5.1 v2 0/1] accel/xen: Fix xen_enabled() behavior on target-agnostic objects Philippe Mathieu-Daudé
2020-08-04 7:49 ` [PATCH-for-5.1 v2 1/1] " Philippe Mathieu-Daudé
2020-08-04 7:57 ` Paul Durrant
2020-08-04 8:34 ` Philippe Mathieu-Daudé [this message]
2020-08-04 8:37 ` Paul Durrant
2020-08-04 9:20 ` Anthony PERARD
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