Re: [Qemu-devel] [PATCH v5 3/3] xen-hvm: Pass is_default to xen_hvm_init

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

On Mon, Jun 09, 2014 at 10:25:36AM -0400, Don Slutz wrote:
> On 06/08/14 11:24, Michael S. Tsirkin wrote:
> >On Fri, Jun 06, 2014 at 01:52:06PM -0400, Don Slutz wrote:
> >>This is the xen part of "pc & q35: Add new machine opt max-ram-below-4g"
> >>
> >>Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> >>Signed-off-by: Don Slutz <dslutz@verizon.com>
> >>---
> >>v5:
> >>   Added Acked-by: Stefano Stabellini
> >>   Minor change of pmc to pcms.
> >>
> >>
> >>  hw/i386/pc_piix.c    |  1 +
> >>  hw/i386/pc_q35.c     |  1 +
> >>  include/hw/xen/xen.h |  2 +-
> >>  xen-hvm-stub.c       |  2 +-
> >>  xen-hvm.c            | 36 ++++++++++++++++++++----------------
> >>  5 files changed, 24 insertions(+), 18 deletions(-)
> >>
> >>diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> >>index 25f4727..27851c6 100644
> >>--- a/hw/i386/pc_piix.c
> >>+++ b/hw/i386/pc_piix.c
> >>@@ -125,6 +125,7 @@ static void pc_init1(MachineState *machine,
> >>      }
> >>      if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size,
> >>+                                      !(pcms && pcms->max_ram_below_4g),
> >>                                        &ram_memory) != 0) {
> >>          fprintf(stderr, "xen hardware virtual machine initialisation failed\n");
> >>          exit(1);
> >>diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
> >>index 155cdf1..6436fce 100644
> >>--- a/hw/i386/pc_q35.c
> >>+++ b/hw/i386/pc_q35.c
> >>@@ -114,6 +114,7 @@ static void pc_q35_init(MachineState *machine)
> >>      }
> >>      if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size,
> >>+                                      !(pcms && pcms->max_ram_below_4g),
> >>                                        &ram_memory) != 0) {
> >>          fprintf(stderr, "xen hardware virtual machine initialisation failed\n");
> >>          exit(1);
> >>diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h
> >>index f71f2d8..6b94c14 100644
> >>--- a/include/hw/xen/xen.h
> >>+++ b/include/hw/xen/xen.h
> >>@@ -41,7 +41,7 @@ void xenstore_store_pv_console_info(int i, struct CharDriverState *chr);
> >>  #if defined(NEED_CPU_H) && !defined(CONFIG_USER_ONLY)
> >>  int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
> >>-                 MemoryRegion **ram_memory);
> >>+                 bool is_default, MemoryRegion **ram_memory);
> >>  void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size,
> >>                     struct MemoryRegion *mr);
> >>  void xen_modified_memory(ram_addr_t start, ram_addr_t length);
> >>diff --git a/xen-hvm-stub.c b/xen-hvm-stub.c
> >>index 2d98696..d1bdb76 100644
> >>--- a/xen-hvm-stub.c
> >>+++ b/xen-hvm-stub.c
> >>@@ -52,7 +52,7 @@ void xen_modified_memory(ram_addr_t start, ram_addr_t length)
> >>  }
> >>  int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
> >>-                 MemoryRegion **ram_memory)
> >>+                 bool is_default, MemoryRegion **ram_memory)
> >>  {
> >>      return 0;
> >>  }
> >>diff --git a/xen-hvm.c b/xen-hvm.c
> >>index a0b6b5d..8d27ee6 100644
> >>--- a/xen-hvm.c
> >>+++ b/xen-hvm.c
> >>@@ -156,31 +156,34 @@ qemu_irq *xen_interrupt_controller_init(void)
> >>  /* Memory Ops */
> >>  static void xen_ram_init(ram_addr_t *below_4g_mem_size,
> >>-                         ram_addr_t *above_4g_mem_size,
> >>+                         ram_addr_t *above_4g_mem_size, bool is_default,
> >>                           ram_addr_t ram_size, MemoryRegion **ram_memory_p)
> >>  {
> >>      MemoryRegion *sysmem = get_system_memory();
> >>      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
> >>+    if (is_default) {
> >>+        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 {
> >>+            *above_4g_mem_size = 0;
> >>+            *below_4g_mem_size = ram_size;
> >>+        }
> >>+    }
> >>+    if (!*above_4g_mem_size) {
> >>+        block_len = ram_size;
> >>+    } else {
> >>+        /*
> >>+         * Xen does not allocate the memory continuously, and keep a hole of
> >>+         * of the size computed above or passed in.
> >>           */
> >Not your fault but this is ambigious.
> >I guess this means "does not allocate the memory continuously, it keeps a
> >hole ..."?
> >
> 
> How does (dropping the double of also):
> 
> Xen does not allocate the memory continuously, it keeps a hole of the size computed above or passed in.
> 
> 
>    -Don Slutz
> 

Sounds reasonable.

> 
> >>-        block_len += HVM_BELOW_4G_MMIO_LENGTH;
> >>+        block_len = (1ULL << 32) + *above_4g_mem_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 {
> >>-        *above_4g_mem_size = 0;
> >>-        *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);
> >>@@ -962,7 +965,7 @@ static void xen_wakeup_notifier(Notifier *notifier, void *data)
> >>  }
> >>  int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
> >>-                 MemoryRegion **ram_memory)
> >>+                 bool is_default, MemoryRegion **ram_memory)
> >>  {
> >>      int i, rc;
> >>      unsigned long ioreq_pfn;
> >>@@ -1040,7 +1043,8 @@ int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
> >>      /* Init RAM management */
> >>      xen_map_cache_init(xen_phys_offset_to_gaddr, state);
> >>-    xen_ram_init(below_4g_mem_size, above_4g_mem_size, ram_size, ram_memory);
> >>+    xen_ram_init(below_4g_mem_size, above_4g_mem_size, is_default, ram_size,
> >>+                 ram_memory);
> >>      qemu_add_vm_change_state_handler(xen_hvm_change_state_handler, state);
> >>-- 
> >>1.8.4