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[Qemu-devel] [PATCH v5 1/6] q35: acpi: do not create dummy MCFG table
From: |
Wei Yang |
Subject: |
[Qemu-devel] [PATCH v5 1/6] q35: acpi: do not create dummy MCFG table |
Date: |
Mon, 20 May 2019 08:59:52 +0800 |
From: Igor Mammedov <address@hidden>
Dummy table (with signature "QEMU") creation came from original SeaBIOS
codebase. And QEMU would have to keep it around if there were Q35 machine
that depended on keeping ACPI tables blob constant size. Luckily there
were no versioned Q35 machine types before commit:
(since 2.3) a1666142db acpi-build: make ROMs RAM blocks resizeable
which obsoleted need to keep ACPI tables blob the same size on
source/destination.
Considering the 1st versioned machine is pc-q35-2.4, the dummy table
is not really necessary and it's safe to drop it without breaking
cross version migration in both directions unconditionally.
Signed-off-by: Igor Mammedov <address@hidden>
Signed-off-by: Wei Yang <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
---
hw/i386/acpi-build.c | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index b4ec14e349..4fb6184cbc 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2413,7 +2413,6 @@ static void
build_mcfg_q35(GArray *table_data, BIOSLinker *linker, AcpiMcfgInfo *info)
{
AcpiTableMcfg *mcfg;
- const char *sig;
int len = sizeof(*mcfg) + 1 * sizeof(mcfg->allocation[0]);
mcfg = acpi_data_push(table_data, len);
@@ -2423,19 +2422,7 @@ build_mcfg_q35(GArray *table_data, BIOSLinker *linker,
AcpiMcfgInfo *info)
mcfg->allocation[0].start_bus_number = 0;
mcfg->allocation[0].end_bus_number = PCIE_MMCFG_BUS(info->mcfg_size - 1);
- /* MCFG is used for ECAM which can be enabled or disabled by guest.
- * To avoid table size changes (which create migration issues),
- * always create the table even if there are no allocations,
- * but set the signature to a reserved value in this case.
- * ACPI spec requires OSPMs to ignore such tables.
- */
- if (info->mcfg_base == PCIE_BASE_ADDR_UNMAPPED) {
- /* Reserved signature: ignored by OSPM */
- sig = "QEMU";
- } else {
- sig = "MCFG";
- }
- build_header(linker, table_data, (void *)mcfg, sig, len, 1, NULL, NULL);
+ build_header(linker, table_data, (void *)mcfg, "MCFG", len, 1, NULL, NULL);
}
/*
@@ -2604,6 +2591,9 @@ static bool acpi_get_mcfg(AcpiMcfgInfo *mcfg)
}
mcfg->mcfg_base = qnum_get_uint(qobject_to(QNum, o));
qobject_unref(o);
+ if (mcfg->mcfg_base == PCIE_BASE_ADDR_UNMAPPED) {
+ return false;
+ }
o = object_property_get_qobject(pci_host, PCIE_HOST_MCFG_SIZE, NULL);
assert(o);
--
2.19.1
- [Qemu-devel] [PATCH v5 0/6] Extract build_mcfg, Wei Yang, 2019/05/19
- [Qemu-devel] [PATCH v5 1/6] q35: acpi: do not create dummy MCFG table,
Wei Yang <=
- [Qemu-devel] [PATCH v5 2/6] hw/arm/virt-acpi-build: remove unnecessary variable mcfg_start, Wei Yang, 2019/05/19
- [Qemu-devel] [PATCH v5 3/6] i386, acpi: remove mcfg_ prefix in AcpiMcfgInfo members, Wei Yang, 2019/05/19
- [Qemu-devel] [PATCH v5 4/6] hw/arm/virt-acpi-build: pass AcpiMcfgInfo to build_mcfg(), Wei Yang, 2019/05/19
- [Qemu-devel] [PATCH v5 5/6] hw/acpi: Consolidate build_mcfg to pci.c, Wei Yang, 2019/05/19
- [Qemu-devel] [PATCH v5 6/6] acpi: pci: use build_append_foo() API to construct MCFG, Wei Yang, 2019/05/19
- Re: [Qemu-devel] [PATCH v5 0/6] Extract build_mcfg, Michael S. Tsirkin, 2019/05/20