[PATCH v2 09/12] libacpi: build ACPI MCFG table if requested

[Joel Upham <jupham125@xxxxxxxxx>]

This adds construct_mcfg() function to libacpi which allows to build MCFG
table for a given mmconfig_addr/mmconfig_len pair if the ACPI_HAS_MCFG
flag was specified in acpi_config struct.

The maximum bus number is calculated from mmconfig_len using
MCFG_SIZE_TO_NUM_BUSES macro (1MByte of MMIO space per bus).

Signed-off-by: Alexey Gerasimenko <x1917x@xxxxxxxxx>
Signed-off-by: Joel Upham <jupham125@xxxxxxxxx>
---
 tools/libacpi/acpi2_0.h | 21 ++++++++++++++++++++
 tools/libacpi/build.c   | 43 +++++++++++++++++++++++++++++++++++++++++
 tools/libacpi/libacpi.h |  4 ++++
 3 files changed, 68 insertions(+)

diff --git a/tools/libacpi/acpi2_0.h b/tools/libacpi/acpi2_0.h
index 6dfa939a8c..02b0cf1098 100644
--- a/tools/libacpi/acpi2_0.h
+++ b/tools/libacpi/acpi2_0.h
@@ -442,6 +442,24 @@ struct acpi_20_slit {
     uint64_t localities;
     uint8_t entry[0];
 };
+/*
+ * PCI Express Memory Mapped Configuration Description Table
+ */
+struct mcfg_range_entry {
+    uint64_t base_address;
+    uint16_t pci_segment;
+    uint8_t  start_pci_bus_num;
+    uint8_t  end_pci_bus_num;
+    uint32_t reserved;
+};
+
+struct acpi_mcfg {
+    struct acpi_header header;
+    uint8_t reserved[8];
+    struct mcfg_range_entry entries[1];
+};
+
+#define MCFG_SIZE_TO_NUM_BUSES(size)  ((size) >> 20)
 
 /*
  * Table Signatures.
@@ -458,6 +476,8 @@ struct acpi_20_slit {
 #define ACPI_2_0_WAET_SIGNATURE ASCII32('W','A','E','T')
 #define ACPI_2_0_SRAT_SIGNATURE ASCII32('S','R','A','T')
 #define ACPI_2_0_SLIT_SIGNATURE ASCII32('S','L','I','T')
+#define ACPI_MCFG_SIGNATURE     ASCII32('M','C','F','G')
+
 
 /*
  * Table revision numbers.
@@ -473,6 +493,7 @@ struct acpi_20_slit {
 #define ACPI_1_0_FADT_REVISION 0x01
 #define ACPI_2_0_SRAT_REVISION 0x01
 #define ACPI_2_0_SLIT_REVISION 0x01
+#define ACPI_1_0_MCFG_REVISION 0x01
 
 #pragma pack ()
 
diff --git a/tools/libacpi/build.c b/tools/libacpi/build.c
index 2f29863db1..fc029d18bf 100644
--- a/tools/libacpi/build.c
+++ b/tools/libacpi/build.c
@@ -295,6 +295,37 @@ static struct acpi_20_slit *construct_slit(struct 
acpi_ctxt *ctxt,
     return slit;
 }
 
+static struct acpi_mcfg *construct_mcfg(struct acpi_ctxt *ctxt,
+                                        const struct acpi_config *config)
+{
+    struct acpi_mcfg *mcfg;
+
+    /* Warning: this code expects that we have only one PCI segment */
+    mcfg = ctxt->mem_ops.alloc(ctxt, sizeof(*mcfg), 16);
+    if (!mcfg)
+        return NULL;
+
+    memset(mcfg, 0, sizeof(*mcfg));
+    mcfg->header.signature    = ACPI_MCFG_SIGNATURE;
+    mcfg->header.revision     = ACPI_1_0_MCFG_REVISION;
+    fixed_strcpy(mcfg->header.oem_id, ACPI_OEM_ID);
+    fixed_strcpy(mcfg->header.oem_table_id, ACPI_OEM_TABLE_ID);
+    mcfg->header.oem_revision = ACPI_OEM_REVISION;
+    mcfg->header.creator_id   = ACPI_CREATOR_ID;
+    mcfg->header.creator_revision = ACPI_CREATOR_REVISION;
+    mcfg->header.length = sizeof(*mcfg);
+
+    mcfg->entries[0].base_address = config->mmconfig_addr;
+    mcfg->entries[0].pci_segment = 0;
+    mcfg->entries[0].start_pci_bus_num = 0;
+    mcfg->entries[0].end_pci_bus_num =
+        MCFG_SIZE_TO_NUM_BUSES(config->mmconfig_len) - 1;
+
+    set_checksum(mcfg, offsetof(struct acpi_header, checksum), sizeof(*mcfg));
+
+    return mcfg;;
+}
+
 static int construct_passthrough_tables(struct acpi_ctxt *ctxt,
                                         unsigned long *table_ptrs,
                                         int nr_tables,
@@ -342,6 +373,7 @@ static int construct_secondary_tables(struct acpi_ctxt 
*ctxt,
     struct acpi_20_hpet *hpet;
     struct acpi_20_waet *waet;
     struct acpi_20_tcpa *tcpa;
+    struct acpi_mcfg *mcfg;
     struct acpi_20_tpm2 *tpm2;
     unsigned char *ssdt;
     void *lasa;
@@ -402,6 +434,17 @@ static int construct_secondary_tables(struct acpi_ctxt 
*ctxt,
         memcpy(ssdt, ssdt_laptop_slate, sizeof(ssdt_laptop_slate));
         table_ptrs[nr_tables++] = ctxt->mem_ops.v2p(ctxt, ssdt);
     }
+
+    /* MCFG */
+    if ( config->table_flags & ACPI_HAS_MCFG )
+    {
+        mcfg = construct_mcfg(ctxt, config);
+        if (!mcfg)
+            return -1;
+
+        table_ptrs[nr_tables++] = ctxt->mem_ops.v2p(ctxt, mcfg);
+    }
+
     /* TPM and its SSDT. */
     if ( config->table_flags & ACPI_HAS_TPM )
     {
diff --git a/tools/libacpi/libacpi.h b/tools/libacpi/libacpi.h
index deda39e5db..b4d3116ca5 100644
--- a/tools/libacpi/libacpi.h
+++ b/tools/libacpi/libacpi.h
@@ -27,6 +27,7 @@
 #define ACPI_HAS_8042              (1<<13)
 #define ACPI_HAS_CMOS_RTC          (1<<14)
 #define ACPI_HAS_SSDT_LAPTOP_SLATE (1<<15)
+#define ACPI_HAS_MCFG              (1<<16)
 
 struct xen_vmemrange;
 struct acpi_numa {
@@ -89,6 +90,9 @@ struct acpi_config {
     uint32_t ioapic_base_address;
     uint16_t pci_isa_irq_mask;
     uint8_t ioapic_id;
+
+    uint64_t mmconfig_addr;
+    uint32_t mmconfig_len;
 };
 
 int acpi_build_tables(struct acpi_ctxt *ctxt, struct acpi_config *config);
-- 
2.34.1