[Xen-devel] [RFC PATCH 03/12] hvmloader: add function to query an emulated machine type (i440/Q35)

[Alexey Gerasimenko <x1917x@xxxxxxxxx>]

This adds a new function get_pc_machine_type() which allows to determine
the emulated chipset type. Supported return values:

- MACHINE_TYPE_I440
- MACHINE_TYPE_Q35
- MACHINE_TYPE_UNKNOWN, results in the error message being printed
  followed by calling BUG() in hvmloader.

Signed-off-by: Alexey Gerasimenko <x1917x@xxxxxxxxx>
---
 tools/firmware/hvmloader/pci_regs.h |  5 ++++
 tools/firmware/hvmloader/util.c     | 47 +++++++++++++++++++++++++++++++++++++
 tools/firmware/hvmloader/util.h     |  8 +++++++
 3 files changed, 60 insertions(+)

diff --git a/tools/firmware/hvmloader/pci_regs.h 
b/tools/firmware/hvmloader/pci_regs.h
index 7bf2d873ab..ba498b840e 100644
--- a/tools/firmware/hvmloader/pci_regs.h
+++ b/tools/firmware/hvmloader/pci_regs.h
@@ -107,6 +107,11 @@
 
 #define PCI_INTEL_OPREGION 0xfc /* 4 bits */
 
+#define PCI_VENDOR_ID_INTEL              0x8086
+#define PCI_DEVICE_ID_INTEL_82441        0x1237
+#define PCI_DEVICE_ID_INTEL_Q35_MCH      0x29c0
+
+
 #endif /* __HVMLOADER_PCI_REGS_H__ */
 
 /*
diff --git a/tools/firmware/hvmloader/util.c b/tools/firmware/hvmloader/util.c
index 0c3f2d24cd..5739a87628 100644
--- a/tools/firmware/hvmloader/util.c
+++ b/tools/firmware/hvmloader/util.c
@@ -22,6 +22,7 @@
 #include "hypercall.h"
 #include "ctype.h"
 #include "vnuma.h"
+#include "pci_regs.h"
 #include <acpi2_0.h>
 #include <libacpi.h>
 #include <stdint.h>
@@ -735,6 +736,52 @@ void __bug(char *file, int line)
     crash();
 }
 
+
+static int machine_type = MACHINE_TYPE_UNDEFINED;
+
+int get_pc_machine_type(void)
+{
+    uint16_t vendor_id;
+    uint16_t device_id;
+
+    if (machine_type != MACHINE_TYPE_UNDEFINED)
+        return machine_type;
+
+    machine_type = MACHINE_TYPE_UNKNOWN;
+
+    vendor_id = pci_readw(0, PCI_VENDOR_ID);
+    device_id = pci_readw(0, PCI_DEVICE_ID);
+
+    /* only Intel platforms are emulated currently */
+    if (vendor_id == PCI_VENDOR_ID_INTEL)
+    {
+        switch (device_id)
+        {
+        case PCI_DEVICE_ID_INTEL_82441:
+            machine_type = MACHINE_TYPE_I440;
+            printf("Detected i440 chipset\n");
+            break;
+
+        case PCI_DEVICE_ID_INTEL_Q35_MCH:
+            machine_type = MACHINE_TYPE_Q35;
+            printf("Detected Q35 chipset\n");
+            break;
+
+        default:
+            break;
+        }
+    }
+
+    if (machine_type == MACHINE_TYPE_UNKNOWN)
+    {
+        printf("Unknown emulated chipset encountered, VID=%04Xh, DID=%04Xh\n",
+               vendor_id, device_id);
+        BUG();
+    }
+
+    return machine_type;
+}
+
 static void validate_hvm_info(struct hvm_info_table *t)
 {
     uint8_t *ptr = (uint8_t *)t;
diff --git a/tools/firmware/hvmloader/util.h b/tools/firmware/hvmloader/util.h
index 7bca6418d2..7c77bedb00 100644
--- a/tools/firmware/hvmloader/util.h
+++ b/tools/firmware/hvmloader/util.h
@@ -100,6 +100,14 @@ void pci_write(uint32_t devfn, uint32_t reg, uint32_t len, 
uint32_t val);
 #define pci_writew(devfn, reg, val) pci_write(devfn, reg, 2, (uint16_t)(val))
 #define pci_writel(devfn, reg, val) pci_write(devfn, reg, 4, (uint32_t)(val))
 
+/* Emulated machine types */
+#define MACHINE_TYPE_UNDEFINED      0
+#define MACHINE_TYPE_I440           1
+#define MACHINE_TYPE_Q35            2
+#define MACHINE_TYPE_UNKNOWN        (-1)
+
+int get_pc_machine_type(void);
+
 /* Get a pointer to the shared-info page */
 struct shared_info *get_shared_info(void) __attribute__ ((const));
 
-- 
2.11.0


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