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[81.2.115.148]) by smtp.gmail.com with ESMTPSA id d1sm5338345wrs.13.2019.03.07.07.24.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Mar 2019 07:24:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=ouZcEyHHWbCH9g8wiJ8EsWwJ4cRIXkH+whqTdb4h1Xw=; b=GXiEpH9k2OjWIJQE3RNxVjzDV2nnHx2B9zY2uhyXnfs46TKXIdPKo0Q/WR2+hhXAdc 6D3lu24DtQLC/vYJuWcw/S1Lqy/Qv5FkiPcEiybDlILgNNLsAKcXHXWVeqbkGNr8fb6Y cmhefK3LdHnEigeH0mmNu/L2ynztExu5hBcvmtan8ksuGWS9VSpxyIDu0kx5kFrYG8VH 6DOIFzfOLEXgbrpjGRrHK/bGrrrexjTMOOc2rNZmNjzz3VGWSBwGSHR7Ugc/1mWTir2c DhV9wU9n7Pa03D58yEiaU98BV1csZPuqmVtyHX7FqmrjP6F7CgdoZlSjaxd9F0f+sTdu bopw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ouZcEyHHWbCH9g8wiJ8EsWwJ4cRIXkH+whqTdb4h1Xw=; b=dky6njDKwDVIfhQuJhMrf/1uqcKeYzlZOjk3uMB3CiXchTCdQdg71NaNWW3tE6PXCe jDsEMEmXDXAincWWsfJpAGKLBLic3xoRTj5C+4jZEQsUQ91N7WxFcL/85a1Q+SRHDnob jR/bhky4VVcyLRVap7L+RqA4wx9UR2JWzVjBpVY4wwz/7rZTTbe/0XenhtS4V9vGJ2Kr wBdDlgzWkWM5p8pbMPcpUux66cgFeAaCcX7xuIKua4ftlmKmg01GC+I+wzHcgPYRF7P+ 51MT8nGnLX/fyQUPMvI0rtH+NNKYjEuBmlDL6iscOMhjuHt/NQKTH/t4AYwAvEumj5+X Swrg== X-Gm-Message-State: APjAAAVpbr5YBFyGmRWPuLIvnu+spgatQmQQZG9GQ8IZcuzuu+XvNbme pfSMyFx7yambDy4qHhJ47w4nakA+fZo= X-Google-Smtp-Source: APXvYqzl/yu2VSZ1Ij6aAfgcqYepdUL98ZalKvVeD+xypBslhp4OwFeordBMVb0Hj+POJUsGQq3+Qw== X-Received: by 2002:a05:600c:2210:: with SMTP id z16mr5992797wml.57.1551972294663; Thu, 07 Mar 2019 07:24:54 -0800 (PST) From: Peter Maydell To: qemu-devel@nongnu.org Date: Thu, 7 Mar 2019 15:24:40 +0000 Message-Id: <20190307152450.20340-3-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190307152450.20340-1-peter.maydell@linaro.org> References: <20190307152450.20340-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:4864:20::343 Subject: [Qemu-devel] [PULL 02/12] docs: Convert memory.txt to rst format X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Convert the memory API documentation from plain text to restructured text format. This is a very minimal conversion: all I had to change was to mark up the ASCII art parts as Sphinx expects for 'literal blocks', and fix up the bulleted lists (Sphinx expects no leading space before the bullet, and wants a blank line before after any list). Signed-off-by: Peter Maydell Reviewed-by: Alex Benn=C3=A9e Acked-by: Aleksandar Markovic Reviewed-by: Richard Henderson Reviewed-by: Cleber Rosa Message-id: 20190305172139.32662-3-peter.maydell@linaro.org Message-id: 20190228145624.24885-3-peter.maydell@linaro.org --- docs/devel/{memory.txt =3D> memory.rst} | 128 ++++++++++++++------------ 1 file changed, 70 insertions(+), 58 deletions(-) rename docs/devel/{memory.txt =3D> memory.rst} (85%) diff --git a/docs/devel/memory.txt b/docs/devel/memory.rst similarity index 85% rename from docs/devel/memory.txt rename to docs/devel/memory.rst index 42577e1d860..b6a4c37ea5e 100644 --- a/docs/devel/memory.txt +++ b/docs/devel/memory.rst @@ -1,19 +1,20 @@ +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D The memory API =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 The memory API models the memory and I/O buses and controllers of a QEMU machine. It attempts to allow modelling of: =20 - - ordinary RAM - - memory-mapped I/O (MMIO) - - memory controllers that can dynamically reroute physical memory regions - to different destinations +- ordinary RAM +- memory-mapped I/O (MMIO) +- memory controllers that can dynamically reroute physical memory regions + to different destinations =20 The memory model provides support for =20 - - tracking RAM changes by the guest - - setting up coalesced memory for kvm - - setting up ioeventfd regions for kvm +- tracking RAM changes by the guest +- setting up coalesced memory for kvm +- setting up ioeventfd regions for kvm =20 Memory is modelled as an acyclic graph of MemoryRegion objects. Sinks (leaves) are RAM and MMIO regions, while other nodes represent @@ -98,25 +99,30 @@ ROM device memory region types), this host memory needs= to be copied to the destination on migration. These APIs which allocate the host memory for you will also register the memory so it is migrated: - - memory_region_init_ram() - - memory_region_init_rom() - - memory_region_init_rom_device() + +- memory_region_init_ram() +- memory_region_init_rom() +- memory_region_init_rom_device() =20 For most devices and boards this is the correct thing. If you have a special case where you need to manage the migration of the backing memory yourself, you can call the functions: - - memory_region_init_ram_nomigrate() - - memory_region_init_rom_nomigrate() - - memory_region_init_rom_device_nomigrate() + +- memory_region_init_ram_nomigrate() +- memory_region_init_rom_nomigrate() +- memory_region_init_rom_device_nomigrate() + which only initialize the MemoryRegion and leave handling migration to the caller. =20 The functions: - - memory_region_init_resizeable_ram() - - memory_region_init_ram_from_file() - - memory_region_init_ram_from_fd() - - memory_region_init_ram_ptr() - - memory_region_init_ram_device_ptr() + +- memory_region_init_resizeable_ram() +- memory_region_init_ram_from_file() +- memory_region_init_ram_from_fd() +- memory_region_init_ram_ptr() +- memory_region_init_ram_device_ptr() + are for special cases only, and so they do not automatically register the backing memory for migration; the caller must manage migration if necessary. @@ -218,7 +224,7 @@ For example, suppose we have a container A of size 0x80= 00 with two subregions B and C. B is a container mapped at 0x2000, size 0x4000, priority 2; C is an MMIO region mapped at 0x0, size 0x6000, priority 1. B currently has two of its own subregions: D of size 0x1000 at offset 0 and E of size 0x1000 at -offset 0x2000. As a diagram: +offset 0x2000. As a diagram:: =20 0 1000 2000 3000 4000 5000 6000 7000 8000 |------|------|------|------|------|------|------|------| @@ -228,8 +234,9 @@ offset 0x2000. As a diagram: D: [DDDDD] E: [EEEEE] =20 -The regions that will be seen within this address range then are: - [CCCCCCCCCCCC][DDDDD][CCCCC][EEEEE][CCCCC] +The regions that will be seen within this address range then are:: + + [CCCCCCCCCCCC][DDDDD][CCCCC][EEEEE][CCCCC] =20 Since B has higher priority than C, its subregions appear in the flat map even where they overlap with C. In ranges where B has not mapped anything @@ -237,8 +244,9 @@ C's region appears. =20 If B had provided its own MMIO operations (ie it was not a pure container) then these would be used for any addresses in its range not handled by -D or E, and the result would be: - [CCCCCCCCCCCC][DDDDD][BBBBB][EEEEE][BBBBB] +D or E, and the result would be:: + + [CCCCCCCCCCCC][DDDDD][BBBBB][EEEEE][BBBBB] =20 Priority values are local to a container, because the priorities of two regions are only compared when they are both children of the same containe= r. @@ -257,6 +265,7 @@ guest accesses an address: =20 - all direct subregions of the root region are matched against the address= , in descending priority order + - if the address lies outside the region offset/size, the subregion is discarded - if the subregion is a leaf (RAM or MMIO), the search terminates, retur= ning @@ -270,36 +279,39 @@ guest accesses an address: address range), then if this is a container with its own MMIO or RAM backing the search terminates, returning the container itself. Otherwi= se we continue with the next subregion in priority order + - if none of the subregions match the address then the search terminates with no match found =20 Example memory map ------------------ =20 -system_memory: container@0-2^48-1 - | - +---- lomem: alias@0-0xdfffffff ---> #ram (0-0xdfffffff) - | - +---- himem: alias@0x100000000-0x11fffffff ---> #ram (0xe0000000-0xffffff= ff) - | - +---- vga-window: alias@0xa0000-0xbffff ---> #pci (0xa0000-0xbffff) - | (prio 1) - | - +---- pci-hole: alias@0xe0000000-0xffffffff ---> #pci (0xe0000000-0xfffff= fff) +:: =20 -pci (0-2^32-1) - | - +--- vga-area: container@0xa0000-0xbffff - | | - | +--- alias@0x00000-0x7fff ---> #vram (0x010000-0x017fff) - | | - | +--- alias@0x08000-0xffff ---> #vram (0x020000-0x027fff) - | - +---- vram: ram@0xe1000000-0xe1ffffff - | - +---- vga-mmio: mmio@0xe2000000-0xe200ffff + system_memory: container@0-2^48-1 + | + +---- lomem: alias@0-0xdfffffff ---> #ram (0-0xdfffffff) + | + +---- himem: alias@0x100000000-0x11fffffff ---> #ram (0xe0000000-0xffff= ffff) + | + +---- vga-window: alias@0xa0000-0xbffff ---> #pci (0xa0000-0xbffff) + | (prio 1) + | + +---- pci-hole: alias@0xe0000000-0xffffffff ---> #pci (0xe0000000-0xfff= fffff) =20 -ram: ram@0x00000000-0xffffffff + pci (0-2^32-1) + | + +--- vga-area: container@0xa0000-0xbffff + | | + | +--- alias@0x00000-0x7fff ---> #vram (0x010000-0x017fff) + | | + | +--- alias@0x08000-0xffff ---> #vram (0x020000-0x027fff) + | + +---- vram: ram@0xe1000000-0xe1ffffff + | + +---- vga-mmio: mmio@0xe2000000-0xe200ffff + + ram: ram@0x00000000-0xffffffff =20 This is a (simplified) PC memory map. The 4GB RAM block is mapped into the system address space via two aliases: "lomem" is a 1:1 mapping of the first @@ -336,16 +348,16 @@ rather than completing successfully; those devices ca= n use the In addition various constraints can be supplied to control how these callbacks are called: =20 - - .valid.min_access_size, .valid.max_access_size define the access sizes - (in bytes) which the device accepts; accesses outside this range will - have device and bus specific behaviour (ignored, or machine check) - - .valid.unaligned specifies that the *device being modelled* supports - unaligned accesses; if false, unaligned accesses will invoke the - appropriate bus or CPU specific behaviour. - - .impl.min_access_size, .impl.max_access_size define the access sizes - (in bytes) supported by the *implementation*; other access sizes will be - emulated using the ones available. For example a 4-byte write will be - emulated using four 1-byte writes, if .impl.max_access_size =3D 1. - - .impl.unaligned specifies that the *implementation* supports unaligned - accesses; if false, unaligned accesses will be emulated by two aligned - accesses. +- .valid.min_access_size, .valid.max_access_size define the access sizes + (in bytes) which the device accepts; accesses outside this range will + have device and bus specific behaviour (ignored, or machine check) +- .valid.unaligned specifies that the *device being modelled* supports + unaligned accesses; if false, unaligned accesses will invoke the + appropriate bus or CPU specific behaviour. +- .impl.min_access_size, .impl.max_access_size define the access sizes + (in bytes) supported by the *implementation*; other access sizes will be + emulated using the ones available. For example a 4-byte write will be + emulated using four 1-byte writes, if .impl.max_access_size =3D 1. +- .impl.unaligned specifies that the *implementation* supports unaligned + accesses; if false, unaligned accesses will be emulated by two aligned + accesses. --=20 2.20.1