x86/EFI: retrieve PCI ROM contents not accessible through BARs

Linux 3.8-rc added code to do this, so we need to support this in the
hypervisor for Dom0 to be able to get at the same information as a
native kernel.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>

3 files changed, 126 insertions, 0 deletions

diff --git a/xen/arch/x86/efi/boot.c b/xen/arch/x86/efi/boot.c
index 10c698c090..725b52c3c7 100644
--- a/xen/arch/x86/efi/boot.c
+++ b/xen/arch/x86/efi/boot.c
@@ -1,5 +1,6 @@
 #include "efi.h"
 #include <efi/efiprot.h>
+#include <efi/efipciio.h>
 #include <public/xen.h>
 #include <xen/compile.h>
 #include <xen/ctype.h>
@@ -8,6 +9,7 @@
 #include <xen/keyhandler.h>
 #include <xen/lib.h>
 #include <xen/multiboot.h>
+#include <xen/pci_regs.h>
 #include <xen/pfn.h>
 #if EFI_PAGE_SIZE != PAGE_SIZE
 # error Cannot use xen/pfn.h here!
@@ -570,6 +572,92 @@ static void __init edd_put_string(u8 *dst, size_t n, const char *src)
 }
 #define edd_put_string(d, s) edd_put_string(d, ARRAY_SIZE(d), s)
 
+static void __init setup_efi_pci(void)
+{
+    EFI_STATUS status;
+    EFI_HANDLE *handles;
+    static EFI_GUID __initdata pci_guid = EFI_PCI_IO_PROTOCOL;
+    UINTN i, nr_pci, size = 0;
+    struct efi_pci_rom *last = NULL;
+
+    status = efi_bs->LocateHandle(ByProtocol, &pci_guid, NULL, &size, NULL);
+    if ( status == EFI_BUFFER_TOO_SMALL )
+        status = efi_bs->AllocatePool(EfiLoaderData, size, (void **)&handles);
+    if ( !EFI_ERROR(status) )
+        status = efi_bs->LocateHandle(ByProtocol, &pci_guid, NULL, &size,
+                                      handles);
+    if ( EFI_ERROR(status) )
+        size = 0;
+
+    nr_pci = size / sizeof(*handles);
+    for ( i = 0; i < nr_pci; ++i )
+    {
+        EFI_PCI_IO *pci = NULL;
+        u64 attributes;
+        struct efi_pci_rom *rom, *va;
+        UINTN segment, bus, device, function;
+
+        status = efi_bs->HandleProtocol(handles[i], &pci_guid, (void **)&pci);
+        if ( EFI_ERROR(status) || !pci || !pci->RomImage || !pci->RomSize )
+            continue;
+
+        status = pci->Attributes(pci, EfiPciIoAttributeOperationGet, 0,
+                                 &attributes);
+        if ( EFI_ERROR(status) ||
+             !(attributes & EFI_PCI_IO_ATTRIBUTE_EMBEDDED_ROM) ||
+             EFI_ERROR(pci->GetLocation(pci, &segment, &bus, &device,
+                       &function)) )
+            continue;
+
+        DisplayUint(segment, 4);
+        PrintStr(L":");
+        DisplayUint(bus, 2);
+        PrintStr(L":");
+        DisplayUint(device, 2);
+        PrintStr(L".");
+        DisplayUint(function, 1);
+        PrintStr(L": ROM: ");
+        DisplayUint(pci->RomSize, 0);
+        PrintStr(L" bytes at ");
+        DisplayUint((UINTN)pci->RomImage, 0);
+        PrintStr(newline);
+
+        size = pci->RomSize + sizeof(*rom);
+        status = efi_bs->AllocatePool(EfiRuntimeServicesData, size,
+                                      (void **)&rom);
+        if ( EFI_ERROR(status) )
+            continue;
+
+        rom->next = NULL;
+        rom->size = pci->RomSize;
+
+        status = pci->Pci.Read(pci, EfiPciIoWidthUint16, PCI_VENDOR_ID, 1,
+                               &rom->vendor);
+        if ( !EFI_ERROR(status) )
+            status = pci->Pci.Read(pci, EfiPciIoWidthUint16, PCI_DEVICE_ID, 1,
+                                   &rom->devid);
+        if ( EFI_ERROR(status) )
+        {
+            efi_bs->FreePool(rom);
+            continue;
+        }
+
+        rom->segment = segment;
+        rom->bus = bus;
+        rom->devfn = (device << 3) | function;
+        memcpy(rom->data, pci->RomImage, pci->RomSize);
+
+        va = (void *)rom + DIRECTMAP_VIRT_START;
+        if ( last )
+            last->next = va;
+        else
+            efi_pci_roms = va;
+        last = rom;
+    }
+
+    efi_bs->FreePool(handles);
+}
+
 static int __init set_color(u32 mask, int bpp, u8 *pos, u8 *sz)
 {
    if ( bpp < 0 )
@@ -1140,6 +1228,9 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
     if (efi.smbios != EFI_INVALID_TABLE_ADDR)
         dmi_efi_get_table((void *)(long)efi.smbios);
 
+    /* Collect PCI ROM contents. */
+    setup_efi_pci();
+
     /* Allocate space for trampoline (in first Mb). */
     cfg.addr = 0x100000;
     cfg.size = trampoline_end - trampoline_start;
diff --git a/xen/arch/x86/efi/efi.h b/xen/arch/x86/efi/efi.h
index 561434e14c..43dbd1728b 100644
--- a/xen/arch/x86/efi/efi.h
+++ b/xen/arch/x86/efi/efi.h
@@ -9,6 +9,14 @@
 #include <xen/spinlock.h>
 #include <asm/page.h>
 
+struct efi_pci_rom {
+    const struct efi_pci_rom *next;
+    u16 vendor, devid, segment;
+    u8 bus, devfn;
+    unsigned long size;
+    unsigned char data[];
+};
+
 extern unsigned int efi_num_ct;
 extern EFI_CONFIGURATION_TABLE *efi_ct;
 
@@ -22,5 +30,7 @@ extern void *efi_memmap;
 
 extern l4_pgentry_t *efi_l4_pgtable;
 
+extern const struct efi_pci_rom *efi_pci_roms;
+
 unsigned long efi_rs_enter(void);
 void efi_rs_leave(unsigned long);
diff --git a/xen/arch/x86/efi/runtime.c b/xen/arch/x86/efi/runtime.c
index b2ff495720..c5b03bfe2c 100644
--- a/xen/arch/x86/efi/runtime.c
+++ b/xen/arch/x86/efi/runtime.c
@@ -37,6 +37,8 @@ struct efi __read_mostly efi = {
 
 l4_pgentry_t *__read_mostly efi_l4_pgtable;
 
+const struct efi_pci_rom *__read_mostly efi_pci_roms;
+
 unsigned long efi_rs_enter(void)
 {
     unsigned long cr3 = read_cr3();
@@ -177,6 +179,29 @@ int efi_get_info(uint32_t idx, union xenpf_efi_info *info)
             }
         }
         return -ESRCH;
+    case XEN_FW_EFI_PCI_ROM: {
+        const struct efi_pci_rom *ent;
+
+        for ( ent = efi_pci_roms; ent; ent = ent->next )
+            if ( info->pci_rom.segment == ent->segment &&
+                 info->pci_rom.bus == ent->bus &&
+                 info->pci_rom.devfn == ent->devfn &&
+                 info->pci_rom.vendor == ent->vendor &&
+                 info->pci_rom.devid == ent->devid )
+            {
+                int rc = 0;
+
+                if ( info->pci_rom.size < ent->size )
+                    rc = -ENOSPC;
+                else if ( copy_to_guest(info->pci_rom.data,
+                                        ent->data, ent->size) )
+                    rc = -EFAULT;
+                info->pci_rom.size = ent->size;
+
+                return rc;
+            }
+        return -ESRCH;
+    }
     default:
         return -EINVAL;
     }