On 11/30/2018 10:53 PM, Michael S. Tsirkin wrote:
On Wed, Nov 21, 2018 at 10:06:06AM +0800, Li Zhijian wrote:
a new field xloadflags was added to recent x86 linux, and BIT 1:
XLF_CAN_BE_LOADED_ABOVE_4G is used to tell bootload that where initrd can be
loaded saftly.
safely
Current QEMU always load
loads
initrd below below_4g_mem_size which
is
always
less than 4G, so here limit
limiting
okay, thanks
initrd_max to 4G - 1 simply is enough if
this bit is set.
CC: Paolo Bonzini <pbonz...@redhat.com>
CC: Richard Henderson <r...@twiddle.net>
CC: Eduardo Habkost <ehabk...@redhat.com>
CC: "Michael S. Tsirkin" <m...@redhat.com>
CC: Marcel Apfelbaum <marcel.apfelb...@gmail.com>
Signed-off-by: Li Zhijian <lizhij...@cn.fujitsu.com>
---
hw/i386/pc.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 2ffe6fb..6d4b973 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -92,6 +92,7 @@
#define FW_CFG_HPET (FW_CFG_ARCH_LOCAL + 4)
#define E820_NR_ENTRIES 16
+#define XLF_CAN_BE_LOADED_ABOVE_4G_MASK (1 << 1)
why not XLF_CAN_BE_LOADED_ABOVE_4G to be consistent
with Linux?
In fact let's import include/uapi/asm/bootparam.h
into standard-headers, and use the macro from there?
Okay, i will import this header at V3
struct e820_entry {
uint64_t address;
@@ -916,6 +917,17 @@ static void load_linux(PCMachineState *pcms,
} else {
initrd_max = 0x37ffffff;
}
+ if (protocol >= 0x20c) {
Let's move it above so we have
if (protocol >= 20c)
else if 0x203
else
Okay
+ unsigned int xloadflags = lduw_p(header+0x236);
+ if (xloadflags & XLF_CAN_BE_LOADED_ABOVE_4G_MASK) {
+ /*
+ * Although kernel allow
allows
initrd loading to above 4G, here we
+ * limit initrd_max to 4G -1
Well not really, it just makes it as large as possible
while still staying below 4G.
due to
since
current QEMU always loads
+ * initrd
It's not QEMU, is it? It's actually the bios ...
Got it, thanks again
Thanks
Zhijian
below pcms->below_4g_mem_size
+ */
+ initrd_max = UINT32_MAX;
+ }
+ }
if (initrd_max >= pcms->below_4g_mem_size - pcmc->acpi_data_size) {
initrd_max = pcms->below_4g_mem_size - pcmc->acpi_data_size - 1;
--
2.7.4
.
