From ff5e61b600d9a130faad32ceda3cd212dcb387d4 Mon Sep 17 00:00:00 2001
From: David Gibson <dgibson@redhat.com>
Date: Thu, 16 Nov 2017 03:07:11 +0100
Subject: [PATCH 07/30] virtio-pci: Replace modern_as with direct access to
modern_bar
RH-Author: David Gibson <dgibson@redhat.com>
Message-id: <20171116030732.8560-2-dgibson@redhat.com>
Patchwork-id: 77689
O-Subject: [PATCH 01/22] virtio-pci: Replace modern_as with direct access to modern_bar
Bugzilla: 1481593
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
From: Alexey Kardashevskiy <aik@ozlabs.ru>
The modern bar is accessed now via yet another address space created just
for that purpose and it does not really need FlatView and dispatch tree
as it has a single memory region so it is just a waste of memory. Things
get even worse when there are dozens or hundreds of virtio-pci devices -
since these address spaces are global, changing any of them triggers
rebuilding all address spaces.
This replaces indirect accesses to the modern BAR with a simple lookup
and direct calls to memory_region_dispatch_read/write.
This is expected to save lots of memory at boot time after applying:
[Qemu-devel] [PULL 00/32] Misc changes for 2017-09-22
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit a93c8d828af186d9a6a1c915a1be8ba22fb89849)
Signed-off-by: David Gibson <dgibson@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
hw/virtio/virtio-pci.c | 75 +++++++++++++++++++++++++++++---------------------
hw/virtio/virtio-pci.h | 17 +++++++-----
2 files changed, 54 insertions(+), 38 deletions(-)
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 6e497c8..4b041bb 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -545,6 +545,24 @@ static const MemoryRegionOps virtio_pci_config_ops = {
.endianness = DEVICE_LITTLE_ENDIAN,
};
+static MemoryRegion *virtio_address_space_lookup(VirtIOPCIProxy *proxy,
+ hwaddr *off, int len)
+{
+ int i;
+ VirtIOPCIRegion *reg;
+
+ for (i = 0; i < ARRAY_SIZE(proxy->regs); ++i) {
+ reg = &proxy->regs[i];
+ if (*off >= reg->offset &&
+ *off + len <= reg->offset + reg->size) {
+ *off -= reg->offset;
+ return ®->mr;
+ }
+ }
+
+ return NULL;
+}
+
/* Below are generic functions to do memcpy from/to an address space,
* without byteswaps, with input validation.
*
@@ -558,63 +576,72 @@ static const MemoryRegionOps virtio_pci_config_ops = {
* Note: host pointer must be aligned.
*/
static
-void virtio_address_space_write(AddressSpace *as, hwaddr addr,
+void virtio_address_space_write(VirtIOPCIProxy *proxy, hwaddr addr,
const uint8_t *buf, int len)
{
- uint32_t val;
+ uint64_t val;
+ MemoryRegion *mr;
/* address_space_* APIs assume an aligned address.
* As address is under guest control, handle illegal values.
*/
addr &= ~(len - 1);
+ mr = virtio_address_space_lookup(proxy, &addr, len);
+ if (!mr) {
+ return;
+ }
+
/* Make sure caller aligned buf properly */
assert(!(((uintptr_t)buf) & (len - 1)));
switch (len) {
case 1:
val = pci_get_byte(buf);
- address_space_stb(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
break;
case 2:
- val = pci_get_word(buf);
- address_space_stw_le(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
+ val = cpu_to_le16(pci_get_word(buf));
break;
case 4:
- val = pci_get_long(buf);
- address_space_stl_le(as, addr, val, MEMTXATTRS_UNSPECIFIED, NULL);
+ val = cpu_to_le32(pci_get_long(buf));
break;
default:
/* As length is under guest control, handle illegal values. */
- break;
+ return;
}
+ memory_region_dispatch_write(mr, addr, val, len, MEMTXATTRS_UNSPECIFIED);
}
static void
-virtio_address_space_read(AddressSpace *as, hwaddr addr, uint8_t *buf, int len)
+virtio_address_space_read(VirtIOPCIProxy *proxy, hwaddr addr,
+ uint8_t *buf, int len)
{
- uint32_t val;
+ uint64_t val;
+ MemoryRegion *mr;
/* address_space_* APIs assume an aligned address.
* As address is under guest control, handle illegal values.
*/
addr &= ~(len - 1);
+ mr = virtio_address_space_lookup(proxy, &addr, len);
+ if (!mr) {
+ return;
+ }
+
/* Make sure caller aligned buf properly */
assert(!(((uintptr_t)buf) & (len - 1)));
+ memory_region_dispatch_read(mr, addr, &val, len, MEMTXATTRS_UNSPECIFIED);
switch (len) {
case 1:
- val = address_space_ldub(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
pci_set_byte(buf, val);
break;
case 2:
- val = address_space_lduw_le(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
- pci_set_word(buf, val);
+ pci_set_word(buf, le16_to_cpu(val));
break;
case 4:
- val = address_space_ldl_le(as, addr, MEMTXATTRS_UNSPECIFIED, NULL);
- pci_set_long(buf, val);
+ pci_set_long(buf, le32_to_cpu(val));
break;
default:
/* As length is under guest control, handle illegal values. */
@@ -650,8 +677,7 @@ static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
if (len == 1 || len == 2 || len == 4) {
assert(len <= sizeof cfg->pci_cfg_data);
- virtio_address_space_write(&proxy->modern_as, off,
- cfg->pci_cfg_data, len);
+ virtio_address_space_write(proxy, off, cfg->pci_cfg_data, len);
}
}
}
@@ -675,8 +701,7 @@ static uint32_t virtio_read_config(PCIDevice *pci_dev,
if (len == 1 || len == 2 || len == 4) {
assert(len <= sizeof cfg->pci_cfg_data);
- virtio_address_space_read(&proxy->modern_as, off,
- cfg->pci_cfg_data, len);
+ virtio_address_space_read(proxy, off, cfg->pci_cfg_data, len);
}
}
@@ -1783,15 +1808,6 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
/* PCI BAR regions must be powers of 2 */
pow2ceil(proxy->notify.offset + proxy->notify.size));
- memory_region_init_alias(&proxy->modern_cfg,
- OBJECT(proxy),
- "virtio-pci-cfg",
- &proxy->modern_bar,
- 0,
- memory_region_size(&proxy->modern_bar));
-
- address_space_init(&proxy->modern_as, &proxy->modern_cfg, "virtio-pci-cfg-as");
-
if (proxy->disable_legacy == ON_OFF_AUTO_AUTO) {
proxy->disable_legacy = pcie_port ? ON_OFF_AUTO_ON : ON_OFF_AUTO_OFF;
}
@@ -1860,10 +1876,7 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
static void virtio_pci_exit(PCIDevice *pci_dev)
{
- VirtIOPCIProxy *proxy = VIRTIO_PCI(pci_dev);
-
msix_uninit_exclusive_bar(pci_dev);
- address_space_destroy(&proxy->modern_as);
}
static void virtio_pci_reset(DeviceState *qdev)
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index 69f5959..12d3a90 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -155,15 +155,18 @@ typedef struct VirtIOPCIQueue {
struct VirtIOPCIProxy {
PCIDevice pci_dev;
MemoryRegion bar;
- VirtIOPCIRegion common;
- VirtIOPCIRegion isr;
- VirtIOPCIRegion device;
- VirtIOPCIRegion notify;
- VirtIOPCIRegion notify_pio;
+ union {
+ struct {
+ VirtIOPCIRegion common;
+ VirtIOPCIRegion isr;
+ VirtIOPCIRegion device;
+ VirtIOPCIRegion notify;
+ VirtIOPCIRegion notify_pio;
+ };
+ VirtIOPCIRegion regs[5];
+ };
MemoryRegion modern_bar;
MemoryRegion io_bar;
- MemoryRegion modern_cfg;
- AddressSpace modern_as;
uint32_t legacy_io_bar_idx;
uint32_t msix_bar_idx;
uint32_t modern_io_bar_idx;
--
1.8.3.1