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From: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
To: qemu-devel@nongnu.org
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
	"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
	"Peter Xu" <peterx@redhat.com>, "Greg Kurz" <groug@kaod.org>,
	qemu-arm@nongnu.org, qemu-ppc@nongnu.org,
	"Cédric Le Goater" <clg@kaod.org>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Hervé Poussineau" <hpoussin@reactos.org>,
	"David Gibson" <david@gibson.dropbear.id.au>
Subject: [RFC PATCH v2 08/11] hw/pci-host/raven: Remove pointless alias mapping onto system bus
Date: Sat, 17 Apr 2021 12:30:25 +0200	[thread overview]
Message-ID: <20210417103028.601124-9-f4bug@amsat.org> (raw)
In-Reply-To: <20210417103028.601124-1-f4bug@amsat.org>

The 'pci-io' alias (mapped with priority 0) ends up masked by
the 'pci-io-non-contiguous' I/O region (mapped with priority 1).

The flatview rendering is ('pci-io-non-contiguous' is written
'pci-io-nc'):

(base addr) [               MemoryRegion               ]        [   FlatView   ]

           +----------------------------+---------------+
           |         priority 0         |   priority 1  |
           +----------------------------+---------------+

8000.0000  +-            +--------------+---------------+      +---------------+
                         |   "pci-io"   |  "pci-io-nc"  |      |  "pci-io-nc"  |
                         |              |               |      |               |
                         | / - isadev   |               |      |               |
                         | | - isadev   |               |      |               |
                         | | - isadev   |               +----> |               |
                         | \ - isadev   |               |      |               |
                         |              |               |      |               |
                         |              |               |      |               |
                         |              |               |      |               |
8080.0000  +-------------+              +---------------+      +---------------+
           |   "pciio"   |              |                      |    "pciio"    |
           |             |              |                      |               |
           |             |              |                      |               |
           |             +  -  -  -  -  |--------------------> |               |
           |             |              |                      |               |
           |             |              |                      |               |
           |             |              |                      |               |
80c0.0000  +-------------+              |                      +---------------+
                         |              |                       +-------------+
                         |              |                       |    "???"    |
                         |              |                       |             |
                         |              |        ???????----->  | unassigned? |
                         |              |                       |             |
                         |              |                       |             |
                         |              |                       |             |
bf80.0000  +-            +--------------+                       +-------------+

The before/after this commit memory tree diff is:

  (qemu) info mtree
  memory-region: system
    0000000000000000-ffffffffffffffff (prio 0, i/o): system
      0000000000000000-0000000001ffffff (prio 0, ram): simm.0
      0000000002000000-0000000003ffffff (prio 1, ram): simm.1
      0000000004000000-0000000005ffffff (prio 2, ram): simm.2
      0000000006000000-0000000007ffffff (prio 3, ram): simm.3
      0000000080000000-00000000807fffff (prio 1, i/o): pci-io-non-contiguous
-     0000000080000000-00000000bf7fffff (prio 0, i/o): alias pci-io @pci-io 0000000000000000-000000003f7fffff
      0000000080800000-0000000080bfffff (prio 0, i/o): pciio
      00000000bfffeff0-00000000bfffeff3 (prio 0, i/o): ppc-parity
      00000000bffffff0-00000000bffffff0 (prio 0, i/o): pci-intack
      00000000c0000000-00000000feffffff (prio 0, i/o): pci-memory
        00000000c00a0000-00000000c00bffff (prio 1, i/o): vga-lowmem
      00000000f0000510-00000000f0000511 (prio 0, i/o): fwcfg.ctl
      00000000f0000512-00000000f0000512 (prio 0, i/o): fwcfg.data
      00000000fff00000-00000000ffffffff (prio 0, rom): bios

We can see it in the monitor, before/after this patch, the
flatview rendering is left unchanged (note the unassigned
80c0.0000-bf7f.ffff range):

  (qemu) info mtree  -f
  FlatView #1
   AS "memory", root: system
   AS "cpu-memory-0", root: system
   Root memory region: system
    0000000000000000-0000000001ffffff (prio 0, ram): simm.0
    0000000002000000-0000000003ffffff (prio 1, ram): simm.1
    0000000004000000-0000000005ffffff (prio 2, ram): simm.2
    0000000006000000-0000000007ffffff (prio 3, ram): simm.3
    0000000080000000-00000000807fffff (prio 1, i/o): pci-io-non-contiguous
    0000000080800000-0000000080bfffff (prio 0, i/o): pciio
    00000000bfffeff0-00000000bfffeff3 (prio 0, i/o): ppc-parity
    00000000bffffff0-00000000bffffff0 (prio 0, i/o): pci-intack
    00000000c00a0000-00000000c00bffff (prio 1, i/o): vga-lowmem
    00000000f0000510-00000000f0000511 (prio 0, i/o): fwcfg.ctl
    00000000f0000512-00000000f0000512 (prio 0, i/o): fwcfg.data
    00000000fff00000-00000000ffffffff (prio 0, rom): bios

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
RFC because I can't justify the unassigned 80c0.0000-bf7f.ffff range.
---
 hw/pci-host/raven.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/hw/pci-host/raven.c b/hw/pci-host/raven.c
index 7bbb7ef0a29..f9c92b83770 100644
--- a/hw/pci-host/raven.c
+++ b/hw/pci-host/raven.c
@@ -67,7 +67,6 @@ struct PRePPCIState {
     PCIBus pci_bus;
     AddressSpace pci_io_as;
     MemoryRegion pci_io;
-    MemoryRegion pci_io_alias;
     MemoryRegion pci_io_non_contiguous;
     MemoryRegion pci_memory;
     MemoryRegion pci_intack;
@@ -299,8 +298,6 @@ static void raven_pcihost_initfn(Object *obj)
     DeviceState *pci_dev;
 
     memory_region_init(&s->pci_io, obj, "pci-io", 0x3f800000);
-    memory_region_init_alias(&s->pci_io_alias, obj, "pci-io",
-                             &s->pci_io, 0, memory_region_size(&s->pci_io));
     memory_region_init_io(&s->pci_io_non_contiguous, obj, &raven_io_ops, s,
                           "pci-io-non-contiguous", 0x00800000);
     memory_region_init(&s->pci_memory, obj, "pci-memory", 0x3f000000);
@@ -308,9 +305,7 @@ static void raven_pcihost_initfn(Object *obj)
 
     /* CPU address space */
     memory_region_add_subregion(address_space_mem, PCI_IO_BASE_ADDR,
-                                &s->pci_io_alias);
-    memory_region_add_subregion_overlap(address_space_mem, PCI_IO_BASE_ADDR,
-                                        &s->pci_io_non_contiguous, 1);
+                                &s->pci_io_non_contiguous);
     memory_region_add_subregion(address_space_mem, 0xc0000000, &s->pci_memory);
     pci_root_bus_new_inplace(&s->pci_bus, sizeof(s->pci_bus), DEVICE(obj), NULL,
                              &s->pci_memory, &s->pci_io, 0, TYPE_PCI_BUS);
-- 
2.26.3



  parent reply	other threads:[~2021-04-17 10:36 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-17 10:30 [PATCH v2 00/11] memory: Forbid mapping AddressSpace root MemoryRegion Philippe Mathieu-Daudé
2021-04-17 10:30 ` [PATCH v2 01/11] hw/arm/aspeed: Do not directly map ram container onto main address bus Philippe Mathieu-Daudé
2021-04-20 18:28   ` Peter Xu
2021-04-21  5:53     ` Cédric Le Goater
2021-04-21 13:02       ` Philippe Mathieu-Daudé
2021-04-17 10:30 ` [PATCH v2 02/11] hw/aspeed/smc: Use the RAM memory region for DMAs Philippe Mathieu-Daudé
2021-04-17 10:30 ` [PATCH v2 03/11] hw/arm/aspeed: Do not sysbus-map mmio flash region directly, use alias Philippe Mathieu-Daudé
2021-04-17 10:30 ` [PATCH v2 04/11] hw/pci-host: Rename Raven ASIC PCI bridge as raven.c Philippe Mathieu-Daudé
2021-04-19  0:46   ` David Gibson
2021-04-17 10:30 ` [PATCH v2 05/11] hw/pci-host/raven: Add PCI_IO_BASE_ADDR definition Philippe Mathieu-Daudé
2021-04-19  0:47   ` David Gibson
2021-04-17 10:30 ` [PATCH v2 06/11] hw/pci-host/raven: Assert PCI I/O AddressSpace is based at 0x80000000 Philippe Mathieu-Daudé
2021-04-19  1:00   ` David Gibson
2021-04-17 10:30 ` [PATCH v2 07/11] hw/pci-host/raven: Use MR alias for AS root, not sysbus mapped MR Philippe Mathieu-Daudé
2021-04-17 10:30 ` Philippe Mathieu-Daudé [this message]
2021-04-17 10:30 ` [PATCH v2 09/11] hw/pci-host/prep: Do not directly map bus-master region onto main bus Philippe Mathieu-Daudé
2021-04-17 10:30 ` [PATCH v2 10/11] memory: Make sure root MR won't be added as subregion Philippe Mathieu-Daudé
2021-04-17 10:30 ` [PATCH v2 11/11] hw/pci-host/raven: Remove temporary assertion 'root MR is zero-based' Philippe Mathieu-Daudé
2021-04-19  7:17 ` [PATCH v2 00/11] memory: Forbid mapping AddressSpace root MemoryRegion Cédric Le Goater
2021-04-19  9:48   ` Philippe Mathieu-Daudé
2021-04-20 19:07 ` Peter Xu

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