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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>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	"Alex Bennée" <alex.bennee@linaro.org>,
	"Alex Williamson" <alex.williamson@redhat.com>,
	"Eduardo Habkost" <eduardo@habkost.net>,
	"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
	"Elena Ufimtseva" <elena.ufimtseva@oracle.com>,
	"Jagannathan Raman" <jag.raman@oracle.com>,
	"Dr. David Alan Gilbert" <dave@treblig.org>,
	"Stefan Zabka" <git@zabka.it>
Subject: [PATCH v3 4/7] physmem: disallow direct access to RAM DEVICE in address_space_write_rom()
Date: Mon, 10 Feb 2025 09:46:45 +0100	[thread overview]
Message-ID: <20250210084648.33798-5-david@redhat.com> (raw)
In-Reply-To: <20250210084648.33798-1-david@redhat.com>

As documented in commit 4a2e242bbb306 ("memory: Don't use memcpy for
ram_device regions"), we disallow direct access to RAM DEVICE regions.

This change implies that address_space_write_rom() and
cpu_memory_rw_debug() won't be able to write to RAM DEVICE regions. It
will also affect cpu_flush_icache_range(), but it's only used by
hw/core/loader.c after writing to ROM, so it is expected to not apply
here with RAM DEVICE.

This fixes direct access to these regions where we don't want direct
access. We'll extend cpu_memory_rw_debug() next to also be able to write to
these (and IO) regions.

This is a preparation for further changes.

Cc: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 system/physmem.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/system/physmem.c b/system/physmem.c
index 67c9db9daa..7cfcc6cafa 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -3137,8 +3137,7 @@ static inline MemTxResult address_space_write_rom_internal(AddressSpace *as,
         l = len;
         mr = address_space_translate(as, addr, &addr1, &l, true, attrs);
 
-        if (!(memory_region_is_ram(mr) ||
-              memory_region_is_romd(mr))) {
+        if (!memory_region_supports_direct_access(mr)) {
             l = memory_access_size(mr, l, addr1);
         } else {
             /* ROM/RAM case */
-- 
2.48.1



  parent reply	other threads:[~2025-02-10  8:48 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-10  8:46 [PATCH v3 0/7] physmem: teach cpu_memory_rw_debug() to write to more memory regions David Hildenbrand
2025-02-10  8:46 ` [PATCH v3 1/7] physmem: factor out memory_region_is_ram_device() check in memory_access_is_direct() David Hildenbrand
2025-02-10  8:46 ` [PATCH v3 2/7] physmem: factor out RAM/ROMD " David Hildenbrand
2025-02-10  8:46 ` [PATCH v3 3/7] physmem: factor out direct access check into memory_region_supports_direct_access() David Hildenbrand
2025-02-10  8:46 ` David Hildenbrand [this message]
2025-02-10  8:46 ` [PATCH v3 5/7] memory: pass MemTxAttrs to memory_access_is_direct() David Hildenbrand
2025-02-12 15:21   ` Peter Xu
2025-02-12 15:36     ` David Hildenbrand
2025-02-10  8:46 ` [PATCH v3 6/7] hmp: use cpu_get_phys_page_debug() in hmp_gva2gpa() David Hildenbrand
2025-02-10  8:46 ` [PATCH v3 7/7] physmem: teach cpu_memory_rw_debug() to write to more memory regions David Hildenbrand
2025-02-11 22:35 ` [PATCH v3 0/7] " Peter Xu
2025-02-12 23:26 ` Stefan Zabka
2025-02-13 12:55   ` David Hildenbrand
2025-02-13 14:51   ` Peter Xu

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