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From: David Hildenbrand <david@redhat.com>
To: qemu-devel@nongnu.org
Cc: "David Hildenbrand" <david@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Peter Xu" <peterx@redhat.com>,
	"Igor Mammedov" <imammedo@redhat.com>,
	"Thiner Logoer" <logoerthiner1@163.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Daniel P . Berrangé" <berrange@redhat.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Elena Ufimtseva" <elena.ufimtseva@oracle.com>,
	"Jagannathan Raman" <jag.raman@oracle.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Ani Sinha" <anisinha@redhat.com>,
	"Xiao Guangrong" <xiaoguangrong.eric@gmail.com>,
	"Daniel Henrique Barboza" <danielhb413@gmail.com>,
	"Greg Kurz" <groug@kaod.org>, "Eric Blake" <eblake@redhat.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Eduardo Habkost" <eduardo@habkost.net>
Subject: [PATCH v4 08/11] docs: Don't mention "-mem-path" in multi-process.rst
Date: Wed,  6 Sep 2023 14:05:00 +0200	[thread overview]
Message-ID: <20230906120503.359863-9-david@redhat.com> (raw)
In-Reply-To: <20230906120503.359863-1-david@redhat.com>

"-mem-path" corresponds to "memory-backend-file,share=off" and,
therefore, creates a private COW mapping of the file. For multi-proces
QEMU, we need proper shared file-backed memory.

Let's make that clearer.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 docs/devel/multi-process.rst | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/docs/devel/multi-process.rst b/docs/devel/multi-process.rst
index e4801751f2..4ef539c0b0 100644
--- a/docs/devel/multi-process.rst
+++ b/docs/devel/multi-process.rst
@@ -409,8 +409,9 @@ the initial messages sent to the emulation process is a guest memory
 table. Each entry in this table consists of a file descriptor and size
 that the emulation process can ``mmap()`` to directly access guest
 memory, similar to ``vhost_user_set_mem_table()``. Note guest memory
-must be backed by file descriptors, such as when QEMU is given the
-*-mem-path* command line option.
+must be backed by shared file-backed memory, for example, using
+*-object memory-backend-file,share=on* and setting that memory backend
+as RAM for the machine.
 
 IOMMU operations
 ^^^^^^^^^^^^^^^^
-- 
2.41.0



  parent reply	other threads:[~2023-09-06 12:07 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-06 12:04 [PATCH v4 00/11] memory-backend-file related improvements and VM templating support David Hildenbrand
2023-09-06 12:04 ` [PATCH v4 01/11] nvdimm: Reject writing label data to ROM instead of crashing QEMU David Hildenbrand
2023-09-06 12:04 ` [PATCH v4 02/11] softmmu/physmem: Distinguish between file access mode and mmap protection David Hildenbrand
2023-09-06 12:04 ` [PATCH v4 03/11] backends/hostmem-file: Add "rom" property to support VM templating with R/O files David Hildenbrand
2023-09-06 12:04 ` [PATCH v4 04/11] softmmu/physmem: Remap with proper protection in qemu_ram_remap() David Hildenbrand
2023-09-06 12:04 ` [PATCH v4 05/11] softmmu/physmem: Bail out early in ram_block_discard_range() with readonly files David Hildenbrand
2023-09-06 12:04 ` [PATCH v4 06/11] softmmu/physmem: Fail creation of new files in file_ram_open() with readonly=true David Hildenbrand
2023-09-06 12:04 ` [PATCH v4 07/11] softmmu/physmem: Never return directories from file_ram_open() David Hildenbrand
2023-09-07 10:31   ` Mario Casquero
2023-09-07 10:35     ` David Hildenbrand
2023-09-06 12:05 ` David Hildenbrand [this message]
2023-09-06 12:05 ` [PATCH v4 09/11] docs: Start documenting VM templating David Hildenbrand
2023-09-06 12:05 ` [PATCH v4 10/11] softmmu/physmem: Hint that "readonly=on, rom=off" exists when opening file R/W for private mapping fails David Hildenbrand
2023-09-06 12:05 ` [PATCH v4 11/11] machine: Improve error message when using default RAM backend id David Hildenbrand
2023-09-11  7:41 ` [PATCH v4 00/11] memory-backend-file related improvements and VM templating support David Hildenbrand

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