Re: [PATCH 1/3] arm/arm64/xen: use C inlines for privcmd_call

From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Julien Grall <julien@xen.org>
Cc: James Morris <jmorris@namei.org>, Sasha Levin <sashal@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	steve.capper@arm.com,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	James Morse <james.morse@arm.com>,
	Vladimir Murzin <vladimir.murzin@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	allison@lohutok.net, info@metux.net, alexios.zavras@intel.com,
	Stefano Stabellini <sstabellini@kernel.org>,
	boris.ostrovsky@oracle.com, jgross@suse.com,
	Stefan Agner <stefan@agner.ch>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	xen-devel@lists.xenproject.org,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>
Subject: Re: [PATCH 1/3] arm/arm64/xen: use C inlines for privcmd_call
Date: Wed, 4 Dec 2019 12:58:20 -0500	[thread overview]
Message-ID: <CA+CK2bBWVLZkFo5e8gQUuiqz_b2oCOtD7-9GkCwf9BsFn9wwaA@mail.gmail.com> (raw)
In-Reply-To: <957930d0-8317-9086-c7a1-8de857f358c2@xen.org>

On Fri, Nov 29, 2019 at 10:05 AM Julien Grall <julien@xen.org> wrote:
>
> Hi,
>
> On 27/11/2019 18:44, Pavel Tatashin wrote:
> > diff --git a/arch/arm64/include/asm/xen/hypercall.h b/arch/arm64/include/asm/xen/hypercall.h
> > index 3522cbaed316..1a74fb28607f 100644
> > --- a/arch/arm64/include/asm/xen/hypercall.h
> > +++ b/arch/arm64/include/asm/xen/hypercall.h
> > @@ -1 +1,29 @@
> > +#ifndef _ASM_ARM64_XEN_HYPERCALL_H
> > +#define _ASM_ARM64_XEN_HYPERCALL_H
> >   #include <xen/arm/hypercall.h>
> > +#include <linux/uaccess.h>
> > +
> > +static inline long privcmd_call(unsigned int call, unsigned long a1,
> > +                             unsigned long a2, unsigned long a3,
> > +                             unsigned long a4, unsigned long a5)
>
> I realize that privcmd_call is the only hypercall using Software PAN at
> the moment. However, dm_op needs the same as hypercall will be issued
> from userspace as well.

The clean-up I am working on now is specific to moving current PAN
useage to C wraps. Once dm_op requires to use PAN it will need to be
used the C variants, because ASM versions are going to be removed by
this series.

>
> So I was wondering whether we should create a generic function (e.g.
> do_xen_hypercall() or do_xen_user_hypercall()) to cover the two hypercalls?
>
> > diff --git a/include/xen/arm/hypercall.h b/include/xen/arm/hypercall.h
> > index b40485e54d80..624c8ad7e42a 100644
> > --- a/include/xen/arm/hypercall.h
> > +++ b/include/xen/arm/hypercall.h
> > @@ -30,8 +30,8 @@
> >    * IN THE SOFTWARE.
> >    */
> >
> > -#ifndef _ASM_ARM_XEN_HYPERCALL_H
> > -#define _ASM_ARM_XEN_HYPERCALL_H
> > +#ifndef _ARM_XEN_HYPERCALL_H
> > +#define _ARM_XEN_HYPERCALL_H
>
> This change feels a bit out of context. Could you split it in a separate
> patch?

Makes sense, I am splitting this into a separate patch.

Thank you,
Pasha