[Qemu-devel] [PULL v2 03/21] pc: pass PCI hole ranges to Guests

["Michael S. Tsirkin" <mst@redhat.com>]

Guest currently has to jump through lots of hoops to guess the PCI hole
ranges.  It's fragile, and makes us change BIOS each time we add a new
chipset.  Let's report the window in a ROM file, to make BIOS do exactly
what QEMU intends.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/i386/pc.c         | 26 ++++++++++++++++++++++++++
 hw/i386/pc_piix.c    | 16 +++++++++++++++-
 hw/i386/pc_q35.c     | 12 ++++++++++--
 include/hw/i386/pc.h |  1 +
 4 files changed, 52 insertions(+), 3 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index c685ee8..e1ed760 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -990,6 +990,31 @@ void pc_cpus_init(const char *cpu_model, DeviceState *icc_bridge)
     }
 }
 
+/* pci-info ROM file. Little endian format */
+typedef struct PcRomPciInfo {
+    uint64_t w32_min;
+    uint64_t w32_max;
+    uint64_t w64_min;
+    uint64_t w64_max;
+} PcRomPciInfo;
+
+static void pc_fw_cfg_guest_info(PcGuestInfo *guest_info)
+{
+    PcRomPciInfo *info;
+    if (!guest_info->has_pci_info) {
+        return;
+    }
+
+    info = g_malloc(sizeof *info);
+    info->w32_min = cpu_to_le64(guest_info->pci_info.w32.begin);
+    info->w32_max = cpu_to_le64(guest_info->pci_info.w32.end);
+    info->w64_min = cpu_to_le64(guest_info->pci_info.w64.begin);
+    info->w64_max = cpu_to_le64(guest_info->pci_info.w64.end);
+    /* Pass PCI hole info to guest via a side channel.
+     * Required so guest PCI enumeration does the right thing. */
+    fw_cfg_add_file(guest_info->fw_cfg, "etc/pci-info", info, sizeof *info);
+}
+
 typedef struct PcGuestInfoState {
     PcGuestInfo info;
     Notifier machine_done;
@@ -1001,6 +1026,7 @@ void pc_guest_info_machine_done(Notifier *notifier, void *data)
     PcGuestInfoState *guest_info_state = container_of(notifier,
                                                       PcGuestInfoState,
                                                       machine_done);
+    pc_fw_cfg_guest_info(&guest_info_state->info);
 }
 
 PcGuestInfo *pc_guest_info_init(ram_addr_t below_4g_mem_size,
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index a70a0d9..d87da95 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -57,6 +57,7 @@ static const int ide_iobase2[MAX_IDE_BUS] = { 0x3f6, 0x376 };
 static const int ide_irq[MAX_IDE_BUS] = { 14, 15 };
 
 static bool has_pvpanic = true;
+static bool has_pci_info = true;
 
 /* PC hardware initialisation */
 static void pc_init1(MemoryRegion *system_memory,
@@ -121,6 +122,7 @@ static void pc_init1(MemoryRegion *system_memory,
     }
 
     guest_info = pc_guest_info_init(below_4g_mem_size, above_4g_mem_size);
+    guest_info->has_pci_info = has_pci_info;
 
     /* Set PCI window size the way seabios has always done it. */
     /* Power of 2 so bios can cover it with a single MTRR */
@@ -258,8 +260,15 @@ static void pc_init_pci(QEMUMachineInitArgs *args)
              initrd_filename, cpu_model, 1, 1);
 }
 
+static void pc_init_pci_1_5(QEMUMachineInitArgs *args)
+{
+    has_pci_info = false;
+    pc_init_pci(args);
+}
+
 static void pc_init_pci_1_4(QEMUMachineInitArgs *args)
 {
+    has_pci_info = false;
     has_pvpanic = false;
     x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
     pc_init_pci(args);
@@ -267,6 +276,7 @@ static void pc_init_pci_1_4(QEMUMachineInitArgs *args)
 
 static void pc_init_pci_1_3(QEMUMachineInitArgs *args)
 {
+    has_pci_info = false;
     enable_compat_apic_id_mode();
     has_pvpanic = false;
     pc_init_pci(args);
@@ -275,6 +285,7 @@ static void pc_init_pci_1_3(QEMUMachineInitArgs *args)
 /* PC machine init function for pc-1.1 to pc-1.2 */
 static void pc_init_pci_1_2(QEMUMachineInitArgs *args)
 {
+    has_pci_info = false;
     disable_kvm_pv_eoi();
     enable_compat_apic_id_mode();
     has_pvpanic = false;
@@ -284,6 +295,7 @@ static void pc_init_pci_1_2(QEMUMachineInitArgs *args)
 /* PC machine init function for pc-0.14 to pc-1.0 */
 static void pc_init_pci_1_0(QEMUMachineInitArgs *args)
 {
+    has_pci_info = false;
     disable_kvm_pv_eoi();
     enable_compat_apic_id_mode();
     has_pvpanic = false;
@@ -300,6 +312,7 @@ static void pc_init_pci_no_kvmclock(QEMUMachineInitArgs *args)
     const char *initrd_filename = args->initrd_filename;
     const char *boot_device = args->boot_device;
     has_pvpanic = false;
+    has_pci_info = false;
     disable_kvm_pv_eoi();
     enable_compat_apic_id_mode();
     pc_init1(get_system_memory(),
@@ -318,6 +331,7 @@ static void pc_init_isa(QEMUMachineInitArgs *args)
     const char *initrd_filename = args->initrd_filename;
     const char *boot_device = args->boot_device;
     has_pvpanic = false;
+    has_pci_info = false;
     if (cpu_model == NULL)
         cpu_model = "486";
     disable_kvm_pv_eoi();
@@ -353,7 +367,7 @@ static QEMUMachine pc_i440fx_machine_v1_6 = {
 static QEMUMachine pc_i440fx_machine_v1_5 = {
     .name = "pc-i440fx-1.5",
     .desc = "Standard PC (i440FX + PIIX, 1996)",
-    .init = pc_init_pci,
+    .init = pc_init_pci_1_5,
     .hot_add_cpu = pc_hot_add_cpu,
     .max_cpus = 255,
     .compat_props = (GlobalProperty[]) {
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index a13acf2..5b92160 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -47,6 +47,7 @@
 #define MAX_SATA_PORTS     6
 
 static bool has_pvpanic = true;
+static bool has_pci_info = true;
 
 /* PC hardware initialisation */
 static void pc_q35_init(QEMUMachineInitArgs *args)
@@ -107,6 +108,7 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     }
 
     guest_info = pc_guest_info_init(below_4g_mem_size, above_4g_mem_size);
+    guest_info->has_pci_info = has_pci_info;
 
     /* allocate ram and load rom/bios */
     if (!xen_enabled()) {
@@ -212,11 +214,17 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     }
 }
 
+static void pc_q35_init_1_5(QEMUMachineInitArgs *args)
+{
+    has_pci_info = false;
+    pc_q35_init(args);
+}
+
 static void pc_q35_init_1_4(QEMUMachineInitArgs *args)
 {
     has_pvpanic = false;
     x86_cpu_compat_set_features("n270", FEAT_1_ECX, 0, CPUID_EXT_MOVBE);
-    pc_q35_init(args);
+    pc_q35_init_1_5(args);
 }
 
 static QEMUMachine pc_q35_machine_v1_6 = {
@@ -232,7 +240,7 @@ static QEMUMachine pc_q35_machine_v1_6 = {
 static QEMUMachine pc_q35_machine_v1_5 = {
     .name = "pc-q35-1.5",
     .desc = "Standard PC (Q35 + ICH9, 2009)",
-    .init = pc_q35_init,
+    .init = pc_q35_init_1_5,
     .hot_add_cpu = pc_hot_add_cpu,
     .max_cpus = 255,
     .compat_props = (GlobalProperty[]) {
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 6cb06fe..ba9ba1a 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -20,6 +20,7 @@ typedef struct PcPciInfo {
 
 struct PcGuestInfo {
     PcPciInfo pci_info;
+    bool has_pci_info;
     FWCfgState *fw_cfg;
 };
 
-- 
MST