[Qemu-devel] [PATCH 0/2] Properly set reset functions for option roms

[Qemu-devel] [PATCH 0/2] Properly set reset functions for option roms

[Glauber Costa]

This series is comprised of two patches:

* The first one, preceeds the second,
* the second one, succeeds the first.

Besides this obvious ordering adventure, they:
 - bring the option rom reset mechanism for kvm. Without it,
   we are not able to reset the machine and have it using its
   boot options again. The code is quite similar to what is in
   qemu-kvm.git
 - allow this mechanism to work with -kernel too. This is currently
   broken, both here and in qemu-kvm.git.

[Qemu-devel] [PATCH 1/2] register reset handler for option_roms

[Glauber Costa]

Currently, boot options are not preserved across a system reset.
option roms can modify themselves, or can for instance restore the real
int 0x19 vector after they tried to boot from it.

To properly do that, we need a reset handler registered to deal with option
roms. This patch is based on current version on qemu-kvm.git

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 hw/pc.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/hw/pc.c b/hw/pc.c
index 61f6e7b..0025474 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -63,6 +63,30 @@ static PITState *pit;
 static IOAPICState *ioapic;
 static PCIDevice *i440fx_state;
 
+typedef struct rom_reset_data {
+    uint8_t *data;
+    target_phys_addr_t addr;
+    unsigned size;
+} RomResetData;
+
+static void option_rom_reset(void *_rrd)
+{
+    RomResetData *rrd = _rrd;
+
+    cpu_physical_memory_write_rom(rrd->addr, rrd->data, rrd->size);
+}
+
+static void option_rom_setup_reset(target_phys_addr_t addr, unsigned size)
+{
+    RomResetData *rrd = qemu_malloc(sizeof *rrd);
+
+    rrd->data = qemu_malloc(size);
+    cpu_physical_memory_read(addr, rrd->data, size);
+    rrd->addr = addr;
+    rrd->size = size;
+    qemu_register_reset(option_rom_reset, rrd);
+}
+
 static void ioport80_write(void *opaque, uint32_t addr, uint32_t data)
 {
 }
@@ -806,6 +830,7 @@ static int load_option_rom(const char *oprom, target_phys_addr_t start,
         }
         /* Round up optiom rom size to the next 2k boundary */
         size = (size + 2047) & ~2047;
+        option_rom_setup_reset(start, size);
         return size;
 }
 
-- 
1.6.2.2

[Qemu-devel] [PATCH 2/2] reset state for load_linux

[Glauber Costa]

The linux loader is just an option rom like any other, just with
some special requirements. Right now, our option rom resetting
mechanism is not being applied to it. As a result, users using
-kernel will not be able to successfully reboot their machines

This patch fixes it by saving all the data we generated in
the load_linux() function, to be used later by the option rom
resetting mechanism.

Signed-off-by: Glauber Costa <glommer@redhat.com>
---
 hw/pc.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/hw/pc.c b/hw/pc.c
index 0025474..6b46427 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -579,6 +579,7 @@ static void generate_bootsect(target_phys_addr_t option_rom,
     rom[sizeof(rom) - 1] = -sum;
 
     cpu_physical_memory_write_rom(option_rom, rom, sizeof(rom));
+    option_rom_setup_reset(option_rom, sizeof (rom));
 }
 
 static long get_file_size(FILE *f)
@@ -746,6 +747,12 @@ static void load_linux(target_phys_addr_t option_rom,
     memset(gpr, 0, sizeof gpr);
     gpr[4] = cmdline_addr-real_addr-16;	/* SP (-16 is paranoia) */
 
+    option_rom_setup_reset(real_addr, setup_size);
+    option_rom_setup_reset(prot_addr, kernel_size);
+    option_rom_setup_reset(cmdline_addr, cmdline_size);
+    if (initrd_filename)
+        option_rom_setup_reset(initrd_addr, initrd_size);
+
     generate_bootsect(option_rom, gpr, seg, 0);
 }
 
-- 
1.6.2.2