[PATCH 0/3] m68k: virt: fix reboot

[PATCH 0/3] m68k: virt: fix reboot

[Laurent Vivier]

This series fixes the reboot of the virt-m68k machine
by correctly initializing the start address and fixing
the ELF kernel image.

The two first patches were already sent last year and
never merged:

https://patchwork.kernel.org/project/qemu-devel/cover/20210429141326.69245-1-laurent@vivier.eu/

Thanks,
Laurent

Laurent Vivier (2):
  hw/elf_ops: clear uninitialized segment space
  m68k: virt: correctly set the initial PC

Philippe Mathieu-Daudé (1):
  exec/memory: Extract address_space_set() from dma_memory_set()

 include/exec/memory.h | 16 ++++++++++++++++
 include/hw/elf_ops.h  | 13 +++++++++++++
 hw/core/loader.c      |  4 ++++
 hw/m68k/virt.c        | 22 +++++++++++++++++-----
 softmmu/dma-helpers.c | 15 +--------------
 softmmu/physmem.c     | 19 +++++++++++++++++++
 6 files changed, 70 insertions(+), 19 deletions(-)

-- 
2.34.1

[PATCH 1/3] exec/memory: Extract address_space_set() from dma_memory_set()

[Laurent Vivier]

From: Philippe Mathieu-Daudé <philmd@redhat.com>

dma_memory_set() does a DMA barrier, set the address space with
a constant value. The constant value filling code is not specific
to DMA and can be used for AddressSpace. Extract it as a new
helper: address_space_set().

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
[lv: rebase]
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 include/exec/memory.h | 16 ++++++++++++++++
 softmmu/dma-helpers.c | 15 +--------------
 softmmu/physmem.c     | 19 +++++++++++++++++++
 3 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 20f1b27377ea..c00c50943107 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -2906,6 +2906,22 @@ address_space_write_cached(MemoryRegionCache *cache, hwaddr addr,
     }
 }
 
+/**
+ * address_space_set: Fill address space with a constant byte.
+ *
+ * Return a MemTxResult indicating whether the operation succeeded
+ * or failed (eg unassigned memory, device rejected the transaction,
+ * IOMMU fault).
+ *
+ * @as: #AddressSpace to be accessed
+ * @addr: address within that address space
+ * @c: constant byte to fill the memory
+ * @len: the number of bytes to fill with the constant byte
+ * @attrs: memory transaction attributes
+ */
+MemTxResult address_space_set(AddressSpace *as, hwaddr addr,
+                              uint8_t c, hwaddr len, MemTxAttrs attrs);
+
 #ifdef NEED_CPU_H
 /* enum device_endian to MemOp.  */
 static inline MemOp devend_memop(enum device_endian end)
diff --git a/softmmu/dma-helpers.c b/softmmu/dma-helpers.c
index b0be1564797f..c2028b658582 100644
--- a/softmmu/dma-helpers.c
+++ b/softmmu/dma-helpers.c
@@ -23,20 +23,7 @@ MemTxResult dma_memory_set(AddressSpace *as, dma_addr_t addr,
 {
     dma_barrier(as, DMA_DIRECTION_FROM_DEVICE);
 
-#define FILLBUF_SIZE 512
-    uint8_t fillbuf[FILLBUF_SIZE];
-    int l;
-    MemTxResult error = MEMTX_OK;
-
-    memset(fillbuf, c, FILLBUF_SIZE);
-    while (len > 0) {
-        l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
-        error |= address_space_write(as, addr, attrs, fillbuf, l);
-        len -= l;
-        addr += l;
-    }
-
-    return error;
+    return address_space_set(as, addr, c, len, attrs);
 }
 
 void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 3524c04c2a16..dddf70edf5d2 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -2927,6 +2927,25 @@ MemTxResult address_space_rw(AddressSpace *as, hwaddr addr, MemTxAttrs attrs,
     }
 }
 
+MemTxResult address_space_set(AddressSpace *as, hwaddr addr,
+                              uint8_t c, hwaddr len, MemTxAttrs attrs)
+{
+#define FILLBUF_SIZE 512
+    uint8_t fillbuf[FILLBUF_SIZE];
+    int l;
+    MemTxResult error = MEMTX_OK;
+
+    memset(fillbuf, c, FILLBUF_SIZE);
+    while (len > 0) {
+        l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE;
+        error |= address_space_write(as, addr, attrs, fillbuf, l);
+        len -= l;
+        addr += l;
+    }
+
+    return error;
+}
+
 void cpu_physical_memory_rw(hwaddr addr, void *buf,
                             hwaddr len, bool is_write)
 {
-- 
2.34.1

[PATCH 2/3] hw/elf_ops: clear uninitialized segment space

[Laurent Vivier]

When the mem_size of the segment is bigger than the file_size,
and if this space doesn't overlap another segment, it needs
to be cleared.

This bug is very similar to the one we had for linux-user,
22d113b52f41 ("linux-user: Fix loading of BSS segments"),
where .bss section is encoded as an extension of the the data
one by setting the segment p_memsz > p_filesz.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
[PMD: Use recently added address_space_set()]
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/hw/elf_ops.h | 13 +++++++++++++
 hw/core/loader.c     |  4 ++++
 2 files changed, 17 insertions(+)

diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h
index 995de8495c27..7c3b1d0f6cc5 100644
--- a/include/hw/elf_ops.h
+++ b/include/hw/elf_ops.h
@@ -555,6 +555,19 @@ static ssize_t glue(load_elf, SZ)(const char *name, int fd,
                     if (res != MEMTX_OK) {
                         goto fail;
                     }
+                    /*
+                     * We need to zero'ify the space that is not copied
+                     * from file
+                     */
+                    if (file_size < mem_size) {
+                        res = address_space_set(as ? as : &address_space_memory,
+                                                addr + file_size, 0,
+                                                mem_size - file_size,
+                                                MEMTXATTRS_UNSPECIFIED);
+                        if (res != MEMTX_OK) {
+                            goto fail;
+                        }
+                    }
                 }
             }
 
diff --git a/hw/core/loader.c b/hw/core/loader.c
index 052a0fd7198b..19edb928e999 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -1164,9 +1164,13 @@ static void rom_reset(void *unused)
         if (rom->mr) {
             void *host = memory_region_get_ram_ptr(rom->mr);
             memcpy(host, rom->data, rom->datasize);
+            memset(host + rom->datasize, 0, rom->romsize - rom->datasize);
         } else {
             address_space_write_rom(rom->as, rom->addr, MEMTXATTRS_UNSPECIFIED,
                                     rom->data, rom->datasize);
+            address_space_set(rom->as, rom->addr + rom->datasize, 0,
+                              rom->romsize - rom->datasize,
+                              MEMTXATTRS_UNSPECIFIED);
         }
         if (rom->isrom) {
             /* rom needs to be written only once */
-- 
2.34.1

[PATCH 3/3] m68k: virt: correctly set the initial PC

[Laurent Vivier]

According to QEMU parameter, set initial PC to the entry of
the loaded kernel.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 hw/m68k/virt.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/hw/m68k/virt.c b/hw/m68k/virt.c
index 78e926a55457..bbaf630bbf20 100644
--- a/hw/m68k/virt.c
+++ b/hw/m68k/virt.c
@@ -85,14 +85,21 @@
 #define VIRT_VIRTIO_MMIO_BASE 0xff010000     /* MMIO: 0xff010000 - 0xff01ffff */
 #define VIRT_VIRTIO_IRQ_BASE  PIC_IRQ(2, 1)  /* PIC: 2, 3, 4, 5, IRQ: ALL */
 
+typedef struct {
+    M68kCPU *cpu;
+    hwaddr initial_pc;
+    hwaddr initial_stack;
+} ResetInfo;
+
 static void main_cpu_reset(void *opaque)
 {
-    M68kCPU *cpu = opaque;
+    ResetInfo *reset_info = opaque;
+    M68kCPU *cpu = reset_info->cpu;
     CPUState *cs = CPU(cpu);
 
     cpu_reset(cs);
-    cpu->env.aregs[7] = ldl_phys(cs->as, 0);
-    cpu->env.pc = ldl_phys(cs->as, 4);
+    cpu->env.aregs[7] = reset_info->initial_stack;
+    cpu->env.pc = reset_info->initial_pc;
 }
 
 static void virt_init(MachineState *machine)
@@ -113,6 +120,7 @@ static void virt_init(MachineState *machine)
     SysBusDevice *sysbus;
     hwaddr io_base;
     int i;
+    ResetInfo *reset_info;
 
     if (ram_size > 3399672 * KiB) {
         /*
@@ -124,9 +132,13 @@ static void virt_init(MachineState *machine)
         exit(1);
     }
 
+    reset_info = g_malloc0(sizeof(ResetInfo));
+
     /* init CPUs */
     cpu = M68K_CPU(cpu_create(machine->cpu_type));
-    qemu_register_reset(main_cpu_reset, cpu);
+
+    reset_info->cpu = cpu;
+    qemu_register_reset(main_cpu_reset, reset_info);
 
     /* RAM */
     memory_region_add_subregion(get_system_memory(), 0, machine->ram);
@@ -206,7 +218,7 @@ static void virt_init(MachineState *machine)
             error_report("could not load kernel '%s'", kernel_filename);
             exit(1);
         }
-        stl_phys(cs->as, 4, elf_entry); /* reset initial PC */
+        reset_info->initial_pc = elf_entry;
         parameters_base = (high + 1) & ~1;
 
         BOOTINFO1(cs->as, parameters_base, BI_MACHTYPE, MACH_VIRT);
-- 
2.34.1

Re: [PATCH 1/3] exec/memory: Extract address_space_set() from dma_memory_set()

[David Hildenbrand]

On 15.01.22 21:37, Laurent Vivier wrote:
> From: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
> dma_memory_set() does a DMA barrier, set the address space with
> a constant value. The constant value filling code is not specific
> to DMA and can be used for AddressSpace. Extract it as a new
> helper: address_space_set().
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> [lv: rebase]
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  include/exec/memory.h | 16 ++++++++++++++++
>  softmmu/dma-helpers.c | 15 +--------------
>  softmmu/physmem.c     | 19 +++++++++++++++++++
>  3 files changed, 36 insertions(+), 14 deletions(-)
> 
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index 20f1b27377ea..c00c50943107 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -2906,6 +2906,22 @@ address_space_write_cached(MemoryRegionCache *cache, hwaddr addr,
>      }
>  }
>  
> +/**
> + * address_space_set: Fill address space with a constant byte.

nit: Fill selected part of an address space with a constant byte.


:)

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb

Re: [PATCH 1/3] exec/memory: Extract address_space_set() from dma_memory_set()

[Peter Xu]

On Sat, Jan 15, 2022 at 09:37:23PM +0100, Laurent Vivier wrote:
> From: Philippe Mathieu-Daudé <philmd@redhat.com>
> 
> dma_memory_set() does a DMA barrier, set the address space with
> a constant value. The constant value filling code is not specific
> to DMA and can be used for AddressSpace. Extract it as a new
> helper: address_space_set().
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> [lv: rebase]
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu

Re: [PATCH 0/3] m68k: virt: fix reboot

[Laurent Vivier]

Le 15/01/2022 à 21:37, Laurent Vivier a écrit :
> This series fixes the reboot of the virt-m68k machine
> by correctly initializing the start address and fixing
> the ELF kernel image.
> 
> The two first patches were already sent last year and
> never merged:
> 
> https://patchwork.kernel.org/project/qemu-devel/cover/20210429141326.69245-1-laurent@vivier.eu/
> 
> Thanks,
> Laurent
> 
> Laurent Vivier (2):
>    hw/elf_ops: clear uninitialized segment space
>    m68k: virt: correctly set the initial PC
> 
> Philippe Mathieu-Daudé (1):
>    exec/memory: Extract address_space_set() from dma_memory_set()
> 
>   include/exec/memory.h | 16 ++++++++++++++++
>   include/hw/elf_ops.h  | 13 +++++++++++++
>   hw/core/loader.c      |  4 ++++
>   hw/m68k/virt.c        | 22 +++++++++++++++++-----
>   softmmu/dma-helpers.c | 15 +--------------
>   softmmu/physmem.c     | 19 +++++++++++++++++++
>   6 files changed, 70 insertions(+), 19 deletions(-)
> 


Applied to my m68k-for-7.0 branch

Thanks,
Laurent