From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Julien Grall <julien@xen.org>
Cc: xen-devel@lists.xenproject.org,
Anthony PERARD <anthony.perard@vates.tech>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Michal Orzel <michal.orzel@amd.com>,
Jan Beulich <jbeulich@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Juergen Gross <jgross@suse.com>,
Christian Lindig <christian.lindig@citrix.com>,
David Scott <dave@recoil.org>,
Bertrand Marquis <bertrand.marquis@arm.com>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Subject: Re: [PATCH 8/9] xen: introduce flag when a domain requires cache control
Date: Tue, 6 May 2025 12:43:45 +0200 [thread overview]
Message-ID: <aBnn4eBSSti7OY56@macbook.lan> (raw)
In-Reply-To: <035eeb54-e03b-463d-8ed8-b7041505322e@xen.org>
On Tue, May 06, 2025 at 11:20:41AM +0100, Julien Grall wrote:
> Hi Roger,
>
> On 06/05/2025 09:31, Roger Pau Monne wrote:
> > Such flag is added to the domain create hypercall, and a matching option is
> > added to xl and libxl to set the flag: `cache_control`. When the flag is
> > set, the domain is allowed the usage of cache control operations.
>
> Can you clarify whether you are talking about using the hypercall to flush
> the cache or the instructions?
On x86 at least: both hypercall and instructions if possible, since
Xen traps cache flush instructions. Maybe that's different on ARM.
As said on a previous reply I've assumed that cache_flush_permitted()
was also relevant on ARM, but maybe it's not and domains are
unconditionally allowed execution of cache control instructions and
hypercalls.
Thanks, Roger.
next prev parent reply other threads:[~2025-05-06 10:43 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-06 8:31 [PATCH 0/8] xen: cache control improvements Roger Pau Monne
2025-05-06 8:31 ` [PATCH 1/9] x86/pv: fix MMUEXT_FLUSH_CACHE to flush all pCPU caches Roger Pau Monne
2025-05-12 14:09 ` Jan Beulich
2025-05-12 14:27 ` Roger Pau Monné
2025-05-12 14:11 ` Jan Beulich
2025-05-12 14:24 ` Roger Pau Monné
2025-05-06 8:31 ` [PATCH 2/9] x86/pv: fix emulation of wb{,no}invd " Roger Pau Monne
2025-05-12 14:20 ` Jan Beulich
2025-05-12 14:41 ` Roger Pau Monné
2025-05-06 8:31 ` [PATCH 3/9] xen/gnttab: limit cache flush operation to guests allowed cache control Roger Pau Monne
2025-05-06 10:15 ` Julien Grall
2025-05-06 10:40 ` Roger Pau Monné
2025-05-12 14:23 ` Jan Beulich
2025-05-06 8:31 ` [PATCH 4/9] x86/gnttab: do not implement GNTTABOP_cache_flush Roger Pau Monne
2025-05-12 14:27 ` Jan Beulich
2025-05-06 8:31 ` [PATCH 5/9] x86/mtrr: use memory_type_changed() in hvm_set_mem_pinned_cacheattr() Roger Pau Monne
2025-05-12 15:04 ` Jan Beulich
2025-05-15 10:22 ` Roger Pau Monné
2025-05-16 7:00 ` Jan Beulich
2025-05-16 7:57 ` Roger Pau Monné
2025-05-16 6:58 ` Jan Beulich
2025-05-16 7:48 ` Roger Pau Monné
2025-05-16 8:02 ` Jan Beulich
2025-05-16 8:45 ` Roger Pau Monné
2025-05-06 8:31 ` [PATCH 6/9] x86/p2m: limit cache flush in memory_type_changed() Roger Pau Monne
2025-05-12 15:10 ` Jan Beulich
2025-05-06 8:31 ` [PATCH 7/9] xen/x86: rename cache_flush_permitted() to has_arch_io_resources() Roger Pau Monne
2025-05-12 15:16 ` Jan Beulich
2025-05-15 10:28 ` Roger Pau Monné
2025-05-16 7:07 ` Jan Beulich
2025-05-16 8:02 ` Roger Pau Monné
2025-05-16 8:08 ` Jan Beulich
2025-05-16 8:27 ` Roger Pau Monné
2025-05-16 8:36 ` Jan Beulich
2025-05-16 8:55 ` Roger Pau Monné
2025-05-06 8:31 ` [PATCH 8/9] xen: introduce flag when a domain requires cache control Roger Pau Monne
2025-05-06 10:20 ` Julien Grall
2025-05-06 10:43 ` Roger Pau Monné [this message]
2025-05-12 15:24 ` Jan Beulich
2025-05-15 10:44 ` Roger Pau Monné
2025-05-16 7:16 ` Jan Beulich
2025-05-16 8:05 ` Roger Pau Monné
2025-05-06 8:31 ` [PATCH 9/9] xen/x86: track dirty pCPU caches for a given vCPU Roger Pau Monne
2025-05-06 11:16 ` Andrew Cooper
2025-05-06 12:55 ` Roger Pau Monné
2025-05-12 15:38 ` Jan Beulich
2025-05-15 10:52 ` Roger Pau Monné
2025-05-16 7:25 ` Jan Beulich
2025-05-12 15:33 ` Jan Beulich
2025-05-06 9:32 ` [PATCH 0/8] xen: cache control improvements Christian Lindig
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