From: Oleksandr <olekstysh@gmail.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: "Oleksandr Tyshchenko" <oleksandr_tyshchenko@epam.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Julien Grall" <julien@xen.org>,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Ian Jackson" <iwj@xenproject.org>, "Wei Liu" <wl@xen.org>,
"Roger Pau Monné" <roger.pau@citrix.com>,
"Julien Grall" <julien.grall@arm.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH V3 16/23] xen/mm: Handle properly reference in set_foreign_p2m_entry() on Arm
Date: Tue, 8 Dec 2020 18:41:57 +0200 [thread overview]
Message-ID: <e9973974-8240-8c28-90cd-2916f3cae25f@gmail.com> (raw)
In-Reply-To: <5f1a2914-f894-0046-2911-9cccb5d94dbf@suse.com>
On 08.12.20 16:24, Jan Beulich wrote:
Hi Jan
> On 30.11.2020 11:31, Oleksandr Tyshchenko wrote:
>> --- a/xen/common/memory.c
>> +++ b/xen/common/memory.c
>> @@ -1134,12 +1134,8 @@ static int acquire_resource(
>> xen_pfn_t mfn_list[32];
>> int rc;
>>
>> - /*
>> - * FIXME: Until foreign pages inserted into the P2M are properly
>> - * reference counted, it is unsafe to allow mapping of
>> - * resource pages unless the caller is the hardware domain.
>> - */
>> - if ( paging_mode_translate(currd) && !is_hardware_domain(currd) )
>> + if ( paging_mode_translate(currd) && !is_hardware_domain(currd) &&
>> + !arch_acquire_resource_check() )
>> return -EACCES;
> Looks like I didn't express myself clearly enough when replying
> to v2, by saying "as both prior parts of the condition should be
> needed only on the x86 side, and there (for PV) there's no p2m
> involved in the refcounting". While one may debate whether the
> hwdom check may remain here, the "translated" one definitely
> should move into the x86 hook. This (I think) will the also make
> apparent that ...
>
>> --- a/xen/include/asm-x86/p2m.h
>> +++ b/xen/include/asm-x86/p2m.h
>> @@ -382,6 +382,19 @@ struct p2m_domain {
>> #endif
>> #include <xen/p2m-common.h>
>>
>> +static inline bool arch_acquire_resource_check(void)
>> +{
>> + /*
>> + * The reference counting of foreign entries in set_foreign_p2m_entry()
>> + * is not supported on x86.
>> + *
>> + * FIXME: Until foreign pages inserted into the P2M are properly
>> + * reference counted, it is unsafe to allow mapping of
>> + * resource pages unless the caller is the hardware domain.
>> + */
>> + return false;
>> +}
> ... the initial part of the comment is true only for translated
> domains. The reference to hwdom in the latter part of the comment
> (which merely gets moved here) is a good indication that the
> hwdom check also wants moving here. In turn the check at the top
> of p2m_add_foreign() should imo then also use this new function,
> instead of effectively open-coding it (with a similar comment).
> And x86's set_foreign_p2m_entry() may want to gain
>
> ASSERT(arch_acquire_resource_check(d));
>
> perhaps alongside the same ASSERT() you add to the Arm variant.
Well, will do. I was about to mention, that new function wanted to gain
domain as parameter, but noticed you had given a hint in the ASSERT
example.
--
Regards,
Oleksandr Tyshchenko
next prev parent reply other threads:[~2020-12-08 16:42 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 10:31 Oleksandr Tyshchenko
2020-11-30 10:31 ` [PATCH V3 01/23] x86/ioreq: Prepare IOREQ feature for making it common Oleksandr Tyshchenko
2020-12-01 11:03 ` Alex Bennée
2020-12-01 18:53 ` Oleksandr
2020-12-01 19:36 ` Alex Bennée
2020-12-02 8:00 ` Jan Beulich
2020-12-02 11:19 ` Oleksandr
2020-12-07 11:13 ` Jan Beulich
2020-12-07 15:27 ` Oleksandr
2020-12-07 16:29 ` Jan Beulich
2020-12-07 17:21 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 02/23] x86/ioreq: Add IOREQ_STATUS_* #define-s and update code for moving Oleksandr Tyshchenko
2020-12-01 11:07 ` Alex Bennée
2020-12-07 11:19 ` Jan Beulich
2020-12-07 15:37 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 03/23] x86/ioreq: Provide out-of-line wrapper for the handle_mmio() Oleksandr Tyshchenko
2020-12-07 11:27 ` Jan Beulich
2020-12-07 15:39 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 04/23] xen/ioreq: Make x86's IOREQ feature common Oleksandr Tyshchenko
2020-12-07 11:41 ` Jan Beulich
2020-12-07 19:43 ` Oleksandr
2020-12-08 9:21 ` Jan Beulich
2020-12-08 13:56 ` Oleksandr
2020-12-08 15:02 ` Jan Beulich
2020-12-08 17:24 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 05/23] xen/ioreq: Make x86's hvm_ioreq_needs_completion() common Oleksandr Tyshchenko
2020-12-07 11:47 ` Jan Beulich
2020-11-30 10:31 ` [PATCH V3 06/23] xen/ioreq: Make x86's hvm_mmio_first(last)_byte() common Oleksandr Tyshchenko
2020-12-07 11:48 ` Jan Beulich
2020-11-30 10:31 ` [PATCH V3 07/23] xen/ioreq: Make x86's hvm_ioreq_(page/vcpu/server) structs common Oleksandr Tyshchenko
2020-12-07 11:54 ` Jan Beulich
2020-11-30 10:31 ` [PATCH V3 08/23] xen/ioreq: Move x86's ioreq_server to struct domain Oleksandr Tyshchenko
2020-12-07 12:04 ` Jan Beulich
2020-12-07 12:12 ` Paul Durrant
2020-12-07 19:52 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 09/23] xen/dm: Make x86's DM feature common Oleksandr Tyshchenko
2020-12-07 12:08 ` Jan Beulich
2020-12-07 20:23 ` Oleksandr
2020-12-08 9:30 ` Jan Beulich
2020-12-08 14:54 ` Oleksandr
2021-01-07 14:38 ` Oleksandr
2021-01-07 15:01 ` Jan Beulich
2021-01-07 16:49 ` Oleksandr
2021-01-12 22:23 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 10/23] xen/mm: Make x86's XENMEM_resource_ioreq_server handling common Oleksandr Tyshchenko
2020-12-07 11:35 ` Jan Beulich
2020-12-07 12:11 ` Jan Beulich
2020-12-07 21:06 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 11/23] xen/ioreq: Move x86's io_completion/io_req fields to struct vcpu Oleksandr Tyshchenko
2020-12-07 12:32 ` Jan Beulich
2020-12-07 20:59 ` Oleksandr
2020-12-08 7:52 ` Paul Durrant
2020-12-08 9:35 ` Jan Beulich
2020-12-08 18:21 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 12/23] xen/ioreq: Remove "hvm" prefixes from involved function names Oleksandr Tyshchenko
2020-12-07 12:45 ` Jan Beulich
2020-12-07 20:28 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 13/23] xen/ioreq: Use guest_cmpxchg64() instead of cmpxchg() Oleksandr Tyshchenko
2020-12-09 21:32 ` Stefano Stabellini
2020-12-09 22:34 ` Oleksandr
2020-12-10 2:30 ` Stefano Stabellini
2020-11-30 10:31 ` [PATCH V3 14/23] arm/ioreq: Introduce arch specific bits for IOREQ/DM features Oleksandr Tyshchenko
2020-12-09 22:04 ` Stefano Stabellini
2020-12-09 22:49 ` Oleksandr
2020-12-10 2:30 ` Stefano Stabellini
2020-11-30 10:31 ` [PATCH V3 15/23] xen/arm: Stick around in leave_hypervisor_to_guest until I/O has completed Oleksandr Tyshchenko
2020-11-30 20:51 ` Volodymyr Babchuk
2020-12-01 12:46 ` Julien Grall
2020-12-09 23:18 ` Stefano Stabellini
2020-12-09 23:35 ` Stefano Stabellini
2020-12-09 23:47 ` Julien Grall
2020-12-10 2:30 ` Stefano Stabellini
2020-12-10 13:17 ` Julien Grall
2020-12-10 13:21 ` Oleksandr
2020-12-09 23:38 ` Julien Grall
2020-11-30 10:31 ` [PATCH V3 16/23] xen/mm: Handle properly reference in set_foreign_p2m_entry() on Arm Oleksandr Tyshchenko
2020-12-08 14:24 ` Jan Beulich
2020-12-08 16:41 ` Oleksandr [this message]
2020-12-09 23:49 ` Stefano Stabellini
2021-01-15 1:18 ` Stefano Stabellini
2020-11-30 10:31 ` [PATCH V3 17/23] xen/ioreq: Introduce domain_has_ioreq_server() Oleksandr Tyshchenko
2020-12-08 15:11 ` Jan Beulich
2020-12-08 15:33 ` Oleksandr
2020-12-08 16:56 ` Oleksandr
2020-12-08 19:43 ` Paul Durrant
2020-12-08 20:16 ` Oleksandr
2020-12-09 9:01 ` Paul Durrant
2020-12-09 18:58 ` Julien Grall
2020-12-09 21:05 ` Oleksandr
2020-12-09 20:36 ` Oleksandr
2020-12-10 8:38 ` Paul Durrant
2020-12-10 16:57 ` Oleksandr
2020-11-30 10:31 ` [PATCH V3 18/23] xen/dm: Introduce xendevicemodel_set_irq_level DM op Oleksandr Tyshchenko
2020-12-10 2:21 ` Stefano Stabellini
2020-12-10 12:58 ` Oleksandr
2020-12-10 13:38 ` Julien Grall
2020-11-30 10:31 ` [PATCH V3 19/23] xen/arm: io: Abstract sign-extension Oleksandr Tyshchenko
2020-11-30 21:03 ` Volodymyr Babchuk
2020-11-30 23:27 ` Oleksandr
2020-12-01 7:55 ` Jan Beulich
2020-12-01 10:30 ` Julien Grall
2020-12-01 10:42 ` Oleksandr
2020-12-01 12:13 ` Julien Grall
2020-12-01 12:24 ` Oleksandr
2020-12-01 12:28 ` Julien Grall
2020-12-01 10:49 ` Jan Beulich
2020-12-01 10:23 ` Julien Grall
2020-11-30 10:31 ` [PATCH V3 20/23] xen/ioreq: Make x86's send_invalidate_req() common Oleksandr Tyshchenko
2020-12-08 15:24 ` Jan Beulich
2020-12-08 16:49 ` Oleksandr
2020-12-09 8:21 ` Jan Beulich
2020-11-30 10:31 ` [PATCH V3 21/23] xen/arm: Add mapcache invalidation handling Oleksandr Tyshchenko
2020-12-10 2:30 ` Stefano Stabellini
2020-12-10 18:50 ` Julien Grall
2020-12-11 1:28 ` Stefano Stabellini
2020-12-11 11:21 ` Oleksandr
2020-12-11 19:07 ` Stefano Stabellini
2020-12-11 19:37 ` Julien Grall
2020-12-11 19:27 ` Julien Grall
2020-11-30 10:31 ` [PATCH V3 22/23] libxl: Introduce basic virtio-mmio support on Arm Oleksandr Tyshchenko
2020-11-30 10:31 ` [PATCH V3 23/23] [RFC] libxl: Add support for virtio-disk configuration Oleksandr Tyshchenko
2020-11-30 11:22 ` [PATCH V3 00/23] IOREQ feature (+ virtio-mmio) on Arm Oleksandr
2020-12-07 13:03 ` Wei Chen
2020-12-07 21:03 ` Oleksandr
2020-11-30 16:21 ` Alex Bennée
2020-11-30 22:22 ` [PATCH V3 00/23] IOREQ feature (+ virtio-mmio) on Arm Oleksandr
2020-12-29 15:32 ` Roger Pau Monné
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