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authorLaszlo Ersek <lersek@redhat.com>2017-06-08 18:10:13 +0200
committerMichael S. Tsirkin <mst@redhat.com>2017-06-16 18:07:08 +0300
commit2f295167e0c429cec233aef7dc8e9fd6f90376df (patch)
tree26a01d1dfe4d8a67bbfe27756db2df062b6ee839 /hw
parentedf8bc98424d62035d5e4c0f39542722d72d7979 (diff)
q35/mch: implement extended TSEG sizes
The q35 machine type currently lets the guest firmware select a 1MB, 2MB or 8MB TSEG (basically, SMRAM) size. In edk2/OVMF, we use 8MB, but even that is not enough when a lot of VCPUs (more than approx. 224) are configured -- SMRAM footprint scales largely proportionally with VCPU count. Introduce a new property for "mch" called "extended-tseg-mbytes", which expresses (in megabytes) the user's choice of TSEG (SMRAM) size. Invent a new, QEMU-specific register in the config space of the DRAM Controller, at offset 0x50, in order to allow guest firmware to query the TSEG (SMRAM) size. According to Intel Document Number 316966-002, Table 5-1 "DRAM Controller Register Address Map (D0:F0)": Warning: Address locations that are not listed are considered Intel Reserved registers locations. Reads to Reserved registers may return non-zero values. Writes to reserved locations may cause system failures. All registers that are defined in the PCI 2.3 specification, but are not necessary or implemented in this component are simply not included in this document. The reserved/unimplemented space in the PCI configuration header space is not documented as such in this summary. Offsets 0x50 and 0x51 are not listed in Table 5-1. They are also not part of the standard PCI config space header. And they precede the capability list as well, which starts at 0xe0 for this device. When the guest writes value 0xffff to this register, the value that can be read back is that of "mch.extended-tseg-mbytes" -- unless it remains 0xffff. The guest is required to write 0xffff first (as opposed to a read-only register) because PCI config space is generally not cleared on QEMU reset, and after S3 resume or reboot, new guest firmware running on old QEMU could read a guest OS-injected value from this register. After reading the available "extended" TSEG size, the guest firmware may actually request that TSEG size by writing pattern 11b to the ESMRAMC register's TSEG_SZ bit-field. (The Intel spec referenced above defines only patterns 00b (1MB), 01b (2MB) and 10b (8MB); 11b is reserved.) On the QEMU command line, the value can be set with -global mch.extended-tseg-mbytes=N The default value for 2.10+ q35 machine types is 16. The value is limited to 0xfff (4095) at the moment, purely so that the product (4095 MB) can be stored to the uint32_t variable "tseg_size" in mch_update_smram(). Users are responsible for choosing sensible TSEG sizes. On 2.9 and earlier q35 machine types, the default value is 0. This lets the 11b bit pattern in ESMRAMC.TSEG_SZ, and the register at offset 0x50, keep their original behavior. When "extended-tseg-mbytes" is nonzero, the new register at offset 0x50 is set to that value on reset, for completeness. PCI config space is migrated automatically, so no VMSD changes are necessary. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1447027 Ref: https://lists.01.org/pipermail/edk2-devel/2017-May/010456.html Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/pci-host/q35.c41
1 files changed, 38 insertions, 3 deletions
diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
index cd5c49616e..28cb97b60f 100644
--- a/hw/pci-host/q35.c
+++ b/hw/pci-host/q35.c
@@ -134,7 +134,7 @@ static void q35_host_get_mmcfg_size(Object *obj, Visitor *v, const char *name,
visit_type_uint32(v, name, &value, errp);
}
-static Property mch_props[] = {
+static Property q35_host_props[] = {
DEFINE_PROP_UINT64(PCIE_HOST_MCFG_BASE, Q35PCIHost, parent_obj.base_addr,
MCH_HOST_BRIDGE_PCIEXBAR_DEFAULT),
DEFINE_PROP_SIZE(PCI_HOST_PROP_PCI_HOLE64_SIZE, Q35PCIHost,
@@ -154,7 +154,7 @@ static void q35_host_class_init(ObjectClass *klass, void *data)
hc->root_bus_path = q35_host_root_bus_path;
dc->realize = q35_host_realize;
- dc->props = mch_props;
+ dc->props = q35_host_props;
/* Reason: needs to be wired up by pc_q35_init */
dc->user_creatable = false;
set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
@@ -369,7 +369,7 @@ static void mch_update_smram(MCHPCIState *mch)
tseg_size = 1024 * 1024 * 8;
break;
default:
- tseg_size = 0;
+ tseg_size = 1024 * 1024 * (uint32_t)mch->ext_tseg_mbytes;
break;
}
} else {
@@ -392,6 +392,17 @@ static void mch_update_smram(MCHPCIState *mch)
memory_region_transaction_commit();
}
+static void mch_update_ext_tseg_mbytes(MCHPCIState *mch)
+{
+ PCIDevice *pd = PCI_DEVICE(mch);
+ uint8_t *reg = pd->config + MCH_HOST_BRIDGE_EXT_TSEG_MBYTES;
+
+ if (mch->ext_tseg_mbytes > 0 &&
+ pci_get_word(reg) == MCH_HOST_BRIDGE_EXT_TSEG_MBYTES_QUERY) {
+ pci_set_word(reg, mch->ext_tseg_mbytes);
+ }
+}
+
static void mch_write_config(PCIDevice *d,
uint32_t address, uint32_t val, int len)
{
@@ -413,6 +424,11 @@ static void mch_write_config(PCIDevice *d,
MCH_HOST_BRIDGE_SMRAM_SIZE)) {
mch_update_smram(mch);
}
+
+ if (ranges_overlap(address, len, MCH_HOST_BRIDGE_EXT_TSEG_MBYTES,
+ MCH_HOST_BRIDGE_EXT_TSEG_MBYTES_SIZE)) {
+ mch_update_ext_tseg_mbytes(mch);
+ }
}
static void mch_update(MCHPCIState *mch)
@@ -420,6 +436,7 @@ static void mch_update(MCHPCIState *mch)
mch_update_pciexbar(mch);
mch_update_pam(mch);
mch_update_smram(mch);
+ mch_update_ext_tseg_mbytes(mch);
}
static int mch_post_load(void *opaque, int version_id)
@@ -457,6 +474,11 @@ static void mch_reset(DeviceState *qdev)
d->wmask[MCH_HOST_BRIDGE_SMRAM] = MCH_HOST_BRIDGE_SMRAM_WMASK;
d->wmask[MCH_HOST_BRIDGE_ESMRAMC] = MCH_HOST_BRIDGE_ESMRAMC_WMASK;
+ if (mch->ext_tseg_mbytes > 0) {
+ pci_set_word(d->config + MCH_HOST_BRIDGE_EXT_TSEG_MBYTES,
+ MCH_HOST_BRIDGE_EXT_TSEG_MBYTES_QUERY);
+ }
+
mch_update(mch);
}
@@ -465,6 +487,12 @@ static void mch_realize(PCIDevice *d, Error **errp)
int i;
MCHPCIState *mch = MCH_PCI_DEVICE(d);
+ if (mch->ext_tseg_mbytes > MCH_HOST_BRIDGE_EXT_TSEG_MBYTES_MAX) {
+ error_setg(errp, "invalid extended-tseg-mbytes value: %" PRIu16,
+ mch->ext_tseg_mbytes);
+ return;
+ }
+
/* setup pci memory mapping */
pc_pci_as_mapping_init(OBJECT(mch), mch->system_memory,
mch->pci_address_space);
@@ -530,6 +558,12 @@ uint64_t mch_mcfg_base(void)
return MCH_HOST_BRIDGE_PCIEXBAR_DEFAULT;
}
+static Property mch_props[] = {
+ DEFINE_PROP_UINT16("extended-tseg-mbytes", MCHPCIState, ext_tseg_mbytes,
+ 16),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
static void mch_class_init(ObjectClass *klass, void *data)
{
PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
@@ -538,6 +572,7 @@ static void mch_class_init(ObjectClass *klass, void *data)
k->realize = mch_realize;
k->config_write = mch_write_config;
dc->reset = mch_reset;
+ dc->props = mch_props;
set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
dc->desc = "Host bridge";
dc->vmsd = &vmstate_mch;