[Qemu-devel] Re: [kvm-devel] [patch 17/24] QEMU/KVM: add cpu_unregister_io_memory and make io mem table index dynamic

[Amit Shah]

This patch broke -no-kvm-irqchip:

* On Wednesday 12 March 2008 01:42:08 Marcelo Tosatti wrote:
> So drivers can clear their mem io table entries on exit back to unassigned
> state.
>
> Also make the io mem index allocation dynamic.
>
> Signed-off-by: Marcelo Tosatti <address@hidden>
>
> Index: kvm-userspace.hotplug2/qemu/cpu-all.h
> ===================================================================
> --- kvm-userspace.hotplug2.orig/qemu/cpu-all.h
> +++ kvm-userspace.hotplug2/qemu/cpu-all.h
> @@ -837,6 +837,7 @@ int cpu_register_io_memory(int io_index,
>                             CPUReadMemoryFunc **mem_read,
>                             CPUWriteMemoryFunc **mem_write,
>                             void *opaque);
> +void cpu_unregister_io_memory(int table_address);
>  CPUWriteMemoryFunc **cpu_get_io_memory_write(int io_index);
>  CPUReadMemoryFunc **cpu_get_io_memory_read(int io_index);
>
> Index: kvm-userspace.hotplug2/qemu/exec.c
> ===================================================================
> --- kvm-userspace.hotplug2.orig/qemu/exec.c
> +++ kvm-userspace.hotplug2/qemu/exec.c
> @@ -158,7 +158,7 @@ PhysPageDesc **l1_phys_map;
>  CPUWriteMemoryFunc *io_mem_write[IO_MEM_NB_ENTRIES][4];
>  CPUReadMemoryFunc *io_mem_read[IO_MEM_NB_ENTRIES][4];
>  void *io_mem_opaque[IO_MEM_NB_ENTRIES];
> -static int io_mem_nb;
> +char io_mem_used[IO_MEM_NB_ENTRIES];
>  #if defined(CONFIG_SOFTMMU)
>  static int io_mem_watch;
>  #endif
> @@ -2498,12 +2498,28 @@ static void *subpage_init (target_phys_a
>      return mmio;
>  }
>
> +static int get_free_io_mem_idx(void)
> +{
> +    int i;
> +
> +    for (i = 0; i<IO_MEM_NB_ENTRIES; i++)
> +        if (!io_mem_used[i]) {
> +            io_mem_used[i] = 1;
> +            return i;
> +        }
> +
> +    return -1;
> +}
> +
>  static void io_mem_init(void)
>  {
> +    int i;
> +
>      cpu_register_io_memory(IO_MEM_ROM >> IO_MEM_SHIFT, error_mem_read,
> unassigned_mem_write, NULL); cpu_register_io_memory(IO_MEM_UNASSIGNED >>
> IO_MEM_SHIFT, unassigned_mem_read, unassigned_mem_write, NULL);
> cpu_register_io_memory(IO_MEM_NOTDIRTY >> IO_MEM_SHIFT, error_mem_read,
> notdirty_mem_write, NULL); -    io_mem_nb = 5;
> +    for (i=0; i<5; i++)
> +        io_mem_used[i] = 0;

The remaining bits (5..IO_MEM_NB_ENTRIES) aren't initialised.

>
>  #if defined(CONFIG_SOFTMMU)
>      io_mem_watch = cpu_register_io_memory(-1, watch_mem_read,
> @@ -2530,9 +2546,9 @@ int cpu_register_io_memory(int io_index,
>      int i, subwidth = 0;
>
>      if (io_index <= 0) {
> -        if (io_mem_nb >= IO_MEM_NB_ENTRIES)
> -            return -1;
> -        io_index = io_mem_nb++;
> +        io_index = get_free_io_mem_idx();
> +        if (io_index == -1)
> +            return io_index;

io_mem_nb was initialised to 5 earlier; we now trample over the first 0..4 
bits.

This fixes the issue; please check for correctness.

From: Amit Shah <address@hidden>
Date: Tue, 18 Mar 2008 18:01:05 +0530
Subject: [PATCH] QEMU/KVM: fix initialization of IO memory regions

Signed-off-by: Amit Shah <address@hidden>
---
 qemu/exec.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/qemu/exec.c b/qemu/exec.c
index edeb21a..be15433 100644
--- a/qemu/exec.c
+++ b/qemu/exec.c
@@ -2502,7 +2502,7 @@ static int get_free_io_mem_idx(void)
 {
     int i;
 
-    for (i = 0; i<IO_MEM_NB_ENTRIES; i++)
+    for (i = 5; i<IO_MEM_NB_ENTRIES; i++)
         if (!io_mem_used[i]) {
             io_mem_used[i] = 1;
             return i;
@@ -2518,7 +2518,7 @@ static void io_mem_init(void)
     cpu_register_io_memory(IO_MEM_ROM >> IO_MEM_SHIFT, error_mem_read, 
unassigned_mem_write, NULL);
     cpu_register_io_memory(IO_MEM_UNASSIGNED >> IO_MEM_SHIFT, 
unassigned_mem_read, unassigned_mem_write, NULL);
     cpu_register_io_memory(IO_MEM_NOTDIRTY >> IO_MEM_SHIFT, error_mem_read, 
notdirty_mem_write, NULL);
-    for (i=0; i<5; i++)
+    for (i=5; i<IO_MEM_NB_ENTRIES; i++)
         io_mem_used[i] = 0;
 
 #if defined(CONFIG_SOFTMMU)
-- 
1.4.4.2