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[Qemu-devel] [PATCH 1/1] vl.c: Add pci_hole_min_size machine option.


From: Don Slutz
Subject: [Qemu-devel] [PATCH 1/1] vl.c: Add pci_hole_min_size machine option.
Date: Thu, 27 Feb 2014 17:32:23 -0500

This allows growing the pci_hole to the size needed.

Signed-off-by: Don Slutz <address@hidden>
---
 hw/i386/pc_piix.c    | 14 ++++++++++++--
 hw/i386/pc_q35.c     | 14 ++++++++++++--
 include/hw/i386/pc.h |  3 +++
 vl.c                 | 16 ++++++++++++++++
 xen-all.c            | 28 +++++++++++++++++-----------
 5 files changed, 60 insertions(+), 15 deletions(-)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index d5dc1ef..58e273d 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -95,6 +95,7 @@ static void pc_init1(QEMUMachineInitArgs *args,
     DeviceState *icc_bridge;
     FWCfgState *fw_cfg = NULL;
     PcGuestInfo *guest_info;
+    ram_addr_t lowmem = 0xe0000000;
 
     if (xen_enabled() && xen_hvm_init(&ram_memory) != 0) {
         fprintf(stderr, "xen hardware virtual machine initialisation 
failed\n");
@@ -111,6 +112,11 @@ static void pc_init1(QEMUMachineInitArgs *args,
         kvmclock_create();
     }
 
+    /* Adjust for pci_hole_min_size */
+    if (pci_hole_min_size > ((1ULL << 32) - lowmem)) {
+        lowmem = (1ULL << 32) - pci_hole_min_size;
+    }
+
     /* Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory).
      * If it doesn't, we need to split it in chunks below and above 4G.
      * In any case, try to make sure that guest addresses aligned at
@@ -118,8 +124,12 @@ static void pc_init1(QEMUMachineInitArgs *args,
      * For old machine types, use whatever split we used historically to avoid
      * breaking migration.
      */
-    if (args->ram_size >= 0xe0000000) {
-        ram_addr_t lowmem = gigabyte_align ? 0xc0000000 : 0xe0000000;
+    if (args->ram_size >= lowmem) {
+        lowmem = gigabyte_align ? 0xc0000000 : 0xe0000000;
+        /* Adjust for pci_hole_min_size */
+        if (pci_hole_min_size > ((1ULL << 32) - lowmem)) {
+            lowmem = (1ULL << 32) - pci_hole_min_size;
+        }
         above_4g_mem_size = args->ram_size - lowmem;
         below_4g_mem_size = lowmem;
     } else {
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index a7f6260..a491f6a 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -82,6 +82,7 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
     PCIDevice *ahci;
     DeviceState *icc_bridge;
     PcGuestInfo *guest_info;
+    ram_addr_t lowmem = 0xb0000000;
 
     if (xen_enabled() && xen_hvm_init(&ram_memory) != 0) {
         fprintf(stderr, "xen hardware virtual machine initialisation 
failed\n");
@@ -97,6 +98,11 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
 
     kvmclock_create();
 
+    /* Adjust for pci_hole_min_size */
+    if (pci_hole_min_size > ((1ULL << 32) - lowmem)) {
+        lowmem = (1ULL << 32) - pci_hole_min_size;
+    }
+
     /* Check whether RAM fits below 4G (leaving 1/2 GByte for IO memory
      * and 256 Mbytes for PCI Express Enhanced Configuration Access Mapping
      * also known as MMCFG).
@@ -106,8 +112,12 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
      * For old machine types, use whatever split we used historically to avoid
      * breaking migration.
      */
-    if (args->ram_size >= 0xb0000000) {
-        ram_addr_t lowmem = gigabyte_align ? 0x80000000 : 0xb0000000;
+    if (args->ram_size >= lowmem) {
+        lowmem = gigabyte_align ? 0x80000000 : 0xb0000000;
+        /* Adjust for pci_hole_min_size */
+        if (pci_hole_min_size > ((1ULL << 32) - lowmem)) {
+            lowmem = (1ULL << 32) - pci_hole_min_size;
+        }
         above_4g_mem_size = args->ram_size - lowmem;
         below_4g_mem_size = lowmem;
     } else {
diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index 9010246..43ea04b 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -204,6 +204,9 @@ int isa_vga_mm_init(hwaddr vram_base,
                     hwaddr ctrl_base, int it_shift,
                     MemoryRegion *address_space);
 
+/* vl.c */
+extern uint64_t pci_hole_min_size;
+
 /* ne2000.c */
 static inline bool isa_ne2000_init(ISABus *bus, int base, int irq, NICInfo *nd)
 {
diff --git a/vl.c b/vl.c
index 1d27b34..32266d3 100644
--- a/vl.c
+++ b/vl.c
@@ -123,6 +123,7 @@ int main(int argc, char **argv)
 #include "qom/object_interfaces.h"
 
 #define DEFAULT_RAM_SIZE 128
+#define MAX_PCI_HOLE_SIZE ((1ULL << 32) - 16 * 1024 * 1024)
 
 #define MAX_VIRTIO_CONSOLES 1
 #define MAX_SCLP_CONSOLES 1
@@ -213,6 +214,7 @@ static NotifierList machine_init_done_notifiers =
 
 static bool tcg_allowed = true;
 bool xen_allowed;
+uint64_t pci_hole_min_size;
 uint32_t xen_domid;
 enum xen_mode xen_mode = XEN_EMULATE;
 static int tcg_tb_size;
@@ -378,6 +380,10 @@ static QemuOptsList qemu_machine_opts = {
             .name = "firmware",
             .type = QEMU_OPT_STRING,
             .help = "firmware image",
+        }, {
+            .name = "pci_hole_min_size",
+            .type = QEMU_OPT_SIZE,
+            .help = "minimum size of PCI mmio hole below 4G",
         },
         { /* End of list */ }
     },
@@ -4050,6 +4056,16 @@ int main(int argc, char **argv, char **envp)
     initrd_filename = qemu_opt_get(machine_opts, "initrd");
     kernel_cmdline = qemu_opt_get(machine_opts, "append");
     bios_name = qemu_opt_get(machine_opts, "firmware");
+    pci_hole_min_size = qemu_opt_get_size(machine_opts,
+                                          "pci_hole_min_size",
+                                          pci_hole_min_size);
+    if (pci_hole_min_size > MAX_PCI_HOLE_SIZE) {
+        fprintf(stderr,
+                "%s: pci_hole_min_size=%llu too big, adjusted to %llu\n",
+                __func__, (unsigned long long) pci_hole_min_size,
+                MAX_PCI_HOLE_SIZE);
+        pci_hole_min_size = MAX_PCI_HOLE_SIZE;
+    }
 
     boot_order = machine->default_boot_order;
     opts = qemu_opts_find(qemu_find_opts("boot-opts"), NULL);
diff --git a/xen-all.c b/xen-all.c
index 4a594bd..dbe24c7 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -155,6 +155,15 @@ qemu_irq *xen_interrupt_controller_init(void)
 
 /* Memory Ops */
 
+static uint64_t mmio_hole_size(void)
+{
+    uint64_t sz = HVM_BELOW_4G_MMIO_LENGTH;
+    if (sz < pci_hole_min_size) {
+        sz = pci_hole_min_size;
+    }
+    return sz;
+}
+
 static void xen_ram_init(ram_addr_t ram_size, MemoryRegion **ram_memory_p)
 {
     MemoryRegion *sysmem = get_system_memory();
@@ -162,23 +171,20 @@ static void xen_ram_init(ram_addr_t ram_size, 
MemoryRegion **ram_memory_p)
     ram_addr_t block_len;
 
     block_len = ram_size;
-    if (ram_size >= HVM_BELOW_4G_RAM_END) {
-        /* Xen does not allocate the memory continuously, and keep a hole at
-         * HVM_BELOW_4G_MMIO_START of HVM_BELOW_4G_MMIO_LENGTH
+    below_4g_mem_size = (1ULL << 32) - mmio_hole_size();
+    if (ram_size < below_4g_mem_size) {
+        below_4g_mem_size = ram_size;
+    } else {
+        above_4g_mem_size = ram_size - below_4g_mem_size;
+        /* Xen does not allocate the memory continuously, and keep a hole of
+         * size mmio_hole_size().
          */
-        block_len += HVM_BELOW_4G_MMIO_LENGTH;
+        block_len += mmio_hole_size();
     }
     memory_region_init_ram(&ram_memory, NULL, "xen.ram", block_len);
     *ram_memory_p = &ram_memory;
     vmstate_register_ram_global(&ram_memory);
 
-    if (ram_size >= HVM_BELOW_4G_RAM_END) {
-        above_4g_mem_size = ram_size - HVM_BELOW_4G_RAM_END;
-        below_4g_mem_size = HVM_BELOW_4G_RAM_END;
-    } else {
-        below_4g_mem_size = ram_size;
-    }
-
     memory_region_init_alias(&ram_640k, NULL, "xen.ram.640k",
                              &ram_memory, 0, 0xa0000);
     memory_region_add_subregion(sysmem, 0, &ram_640k);
-- 
1.8.4




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