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Re: [Xen-devel] [PATCH v2 4/4] xen-all: Pass max_ram_below_4g to xen_hvm_init.
On 03/16/14 12:10, Stefano Stabellini wrote:
On Tue, 11 Mar 2014, Don Slutz wrote:
This is the xen part of "pc & q35: Add new object pc-memory-layout."
Signed-off-by: Don Slutz<dslutz@xxxxxxxxxxx>
---
hw/i386/pc_piix.c | 4 ++--
hw/i386/pc_q35.c | 4 ++--
include/hw/xen/xen.h | 4 ++--
xen-all.c | 41 ++++++++++++++++++++++-------------------
xen-stub.c | 4 ++--
5 files changed, 30 insertions(+), 27 deletions(-)
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 964ea33..691fc5d 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -131,8 +131,8 @@ static void pc_init1(QEMUMachineInitArgs *args,
below_4g_mem_size = args->ram_size;
}
- if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size,
- &ram_memory) != 0) {
+ if (xen_enabled() && xen_hvm_init(max_ram_below_4g, &below_4g_mem_size,
+ &above_4g_mem_size, &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 c95e6e2..8e1c417 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -120,8 +120,8 @@ static void pc_q35_init(QEMUMachineInitArgs *args)
below_4g_mem_size = args->ram_size;
}
- if (xen_enabled() && xen_hvm_init(&below_4g_mem_size, &above_4g_mem_size,
- &ram_memory) != 0) {
+ if (xen_enabled() && xen_hvm_init(max_ram_below_4g, &below_4g_mem_size,
+ &above_4g_mem_size, &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 0769db2..fda559a 100644
--- a/include/hw/xen/xen.h
+++ b/include/hw/xen/xen.h
@@ -41,8 +41,8 @@ int xen_init(QEMUMachine *machine);
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);
+int xen_hvm_init(ram_addr_t max_ram_below_4g, ram_addr_t *below_4g_mem_size,
+ ram_addr_t *above_4g_mem_size, 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-all.c b/xen-all.c
index c64300c..48ba335 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -155,32 +155,34 @@ qemu_irq *xen_interrupt_controller_init(void)
/* Memory Ops */
-static void xen_ram_init(ram_addr_t *below_4g_mem_size,
+static void xen_ram_init(ram_addr_t ram_size, ram_addr_t max_ram_below_4g,
+ ram_addr_t *below_4g_mem_size,
ram_addr_t *above_4g_mem_size,
- ram_addr_t ram_size, MemoryRegion **ram_memory_p)
+ 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
- */
- block_len += HVM_BELOW_4G_MMIO_LENGTH;
+ if (!max_ram_below_4g) {
+ 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;
+ }
+ }
Instead of treating max_ram_below_4g as a special case, couldn't
initialize it to HVM_BELOW_4G_RAM_END?
Since max_ram_below_4g is used and initialize in normal QEMU code
where HVM_BELOW_4G_RAM_END is not defined, I do not see how to
do this outside of this routine without adding a new routine for this.
We could consider HVM_BELOW_4G_RAM_END as the upper bound of
max_ram_below_4g.
Yes. Currently the only limit on max_ram_below_4g is 4G. I am on
the fence on this. I think there are valid values > HVM_BELOW_4G_RAM_END,
but not clear they need to be supported.
I would just change the code to:
if (ram_size >= max_ram_below_4g) {
above_4g_mem_size = ram_size - max_ram_below_4g;
below_4g_mem_size = max_ram_below_4g;
} else {
below_4g_mem_size = ram_size;
}
This is the code that is in patch #3 in the normal QEMU path but using
the variable lowmem so that xen can know if max_ram_below_4g was
set to non-zero. The issue that I am looking at handling here is the case
of an older xen (does not know about max_ram_below_4g) and the
newer QEMU, where xen expects QEMUs memory layout to change to
HVM_BELOW_4G_RAM_END.
Because of this (QEMU is doing the right thing if max_ram_below_4g is
non-zero) is why I coded it as only when max_ram_below_4g is zero, the
xen default is not the same as QEMU.
-Don Slutz
+ 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. */
+ 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);
@@ -1069,8 +1071,8 @@ static void xen_wakeup_notifier(Notifier *notifier, void
*data)
xc_set_hvm_param(xen_xc, xen_domid, HVM_PARAM_ACPI_S_STATE, 0);
}
-int xen_hvm_init(ram_addr_t *below_4g_mem_size, ram_addr_t *above_4g_mem_size,
- MemoryRegion **ram_memory)
+int xen_hvm_init(ram_addr_t max_ram_below_4g, ram_addr_t *below_4g_mem_size,
+ ram_addr_t *above_4g_mem_size, MemoryRegion **ram_memory)
{
int i, rc;
unsigned long ioreq_pfn;
@@ -1148,7 +1150,8 @@ 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(ram_size, max_ram_below_4g, below_4g_mem_size,
+ above_4g_mem_size, ram_memory);
qemu_add_vm_change_state_handler(xen_hvm_change_state_handler, state);
diff --git a/xen-stub.c b/xen-stub.c
index 0302dff..dd317a5 100644
--- a/xen-stub.c
+++ b/xen-stub.c
@@ -64,8 +64,8 @@ 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)
+int xen_hvm_init(ram_addr_t max_ram_below_4g, ram_addr_t *below_4g_mem_size,
+ ram_addr_t *above_4g_mem_size, MemoryRegion **ram_memory)
{
return 0;
}
--
1.8.4
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