From: Jan Beulich <jbeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
"George Dunlap" <George.Dunlap@eu.citrix.com>,
"Ian Jackson" <iwj@xenproject.org>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Wei Liu" <wl@xen.org>, "Julien Grall" <julien@xen.org>,
"Paul Durrant" <paul@xen.org>,
"Michał Leszczyński" <michal.leszczynski@cert.pl>,
"Hubert Jasudowicz" <hubert.jasudowicz@cert.pl>,
"Tamas K Lengyel" <tamas@tklengyel.com>
Subject: Re: [PATCH v2 07/11] xen/memory: Improve compat XENMEM_acquire_resource handling
Date: Mon, 28 Sep 2020 11:09:53 +0200 [thread overview]
Message-ID: <9b6c7ed2-02a4-f422-c0ab-62ca5864c7db@suse.com> (raw)
In-Reply-To: <20200922182444.12350-8-andrew.cooper3@citrix.com>
On 22.09.2020 20:24, Andrew Cooper wrote:
> @@ -446,6 +430,31 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat)
>
> #undef XLAT_mem_acquire_resource_HNDL_frame_list
>
> + if ( xen_frame_list && cmp.mar.nr_frames )
> + {
> + /*
> + * frame_list is an input for translated guests, and an output
> + * for untranslated guests. Only copy in for translated guests.
> + */
> + if ( paging_mode_translate(currd) )
> + {
> + compat_pfn_t *compat_frame_list = (void *)xen_frame_list;
> +
> + if ( !compat_handle_okay(cmp.mar.frame_list,
> + cmp.mar.nr_frames) ||
> + __copy_from_compat_offset(
> + compat_frame_list, cmp.mar.frame_list,
> + 0, cmp.mar.nr_frames) )
> + return -EFAULT;
> +
> + /*
> + * Iterate backwards over compat_frame_list[] expanding
> + * compat_pfn_t to xen_pfn_t in place.
> + */
> + for ( int x = cmp.mar.nr_frames - 1; x >= 0; --x )
> + xen_frame_list[x] = compat_frame_list[x];
In addition to what Paul has said, I also don't see why you resort
to a signed type here. Using the available local variable i ought to
be quite easy:
for ( i = cmp.mar.nr_frames; i--; )
xen_frame_list[i] = compat_frame_list[i];
As an aside, considering the controversy we're having on patch 2, I
find it quite interesting how you carefully allow for nr_frames being
zero throughout your changes here (which, as I think is obvious, I
agree you want to do).
Jan
next prev parent reply other threads:[~2020-09-28 9:10 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 18:24 [PATCH v2 00/11] Multiple fixes to XENMEM_acquire_resource Andrew Cooper
2020-09-22 18:24 ` [PATCH v2 01/11] xen/memory: Introduce CONFIG_ARCH_ACQUIRE_RESOURCE Andrew Cooper
2020-09-22 18:24 ` [PATCH v2 02/11] xen/gnttab: Rework resource acquisition Andrew Cooper
2020-09-24 9:51 ` Paul Durrant
2021-01-11 21:22 ` Andrew Cooper
2021-01-12 8:23 ` Jan Beulich
2021-01-12 20:06 ` Andrew Cooper
2021-01-12 8:29 ` Paul Durrant
2020-09-25 13:17 ` Jan Beulich
2021-01-11 21:22 ` Andrew Cooper
2021-01-12 8:15 ` Jan Beulich
2021-01-12 18:11 ` Andrew Cooper
2020-09-22 18:24 ` [PATCH v2 03/11] xen/memory: Fix compat XENMEM_acquire_resource for size requests Andrew Cooper
2020-09-22 18:24 ` [PATCH v2 04/11] xen/memory: Fix acquire_resource size semantics Andrew Cooper
2020-09-24 10:06 ` Paul Durrant
2020-09-24 10:57 ` Andrew Cooper
2020-09-24 11:04 ` Paul Durrant
2020-09-25 15:56 ` Jan Beulich
2020-09-22 18:24 ` [PATCH v2 05/11] tools/foreignmem: Support querying the size of a resource Andrew Cooper
2021-01-08 17:52 ` Andrew Cooper
2021-01-11 10:50 ` Roger Pau Monné
2021-01-11 15:00 ` Andrew Cooper
2021-01-11 15:26 ` [PATCH v3 " Andrew Cooper
2021-01-11 15:54 ` Roger Pau Monné
2020-09-22 18:24 ` [PATCH v2 06/11] xen/memory: Clarify the XENMEM_acquire_resource ABI description Andrew Cooper
2020-09-24 10:08 ` Paul Durrant
2020-09-22 18:24 ` [PATCH v2 07/11] xen/memory: Improve compat XENMEM_acquire_resource handling Andrew Cooper
2020-09-24 10:16 ` Paul Durrant
2020-09-28 9:09 ` Jan Beulich [this message]
2021-01-08 18:57 ` Andrew Cooper
2021-01-11 14:25 ` Jan Beulich
2020-09-22 18:24 ` [PATCH v2 08/11] xen/memory: Indent part of acquire_resource() Andrew Cooper
2020-09-24 10:36 ` Paul Durrant
2020-09-22 18:24 ` [PATCH v2 09/11] xen/memory: Fix mapping grant tables with XENMEM_acquire_resource Andrew Cooper
2020-09-24 10:47 ` Paul Durrant
2021-01-08 19:36 ` Andrew Cooper
2020-09-28 9:37 ` Jan Beulich
2021-01-11 20:05 ` Andrew Cooper
2021-01-11 22:36 ` Andrew Cooper
2021-01-12 8:39 ` Jan Beulich
2020-09-22 18:24 ` [PATCH v2 10/11] TESTING dom0 Andrew Cooper
2020-09-22 18:24 ` [PATCH v2 11/11] TESTING XTF Andrew Cooper
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