Re: [Qemu-devel] [PATCH v3] PPC: e500: Fix duplicate kernel load and device tree overlap

[David Engraf]

Am 02.03.2018 um 02:45 schrieb David Gibson:

On Thu, Feb 15, 2018 at 10:36:00AM +0100, David Engraf wrote:

This patch fixes an incorrect behavior when the -kernel argument has been
specified without -bios. In this case the kernel was loaded twice. At address
32M as a raw image and afterwards by load_elf/load_uimage at the
corresponding load address. In this case the region for the device tree and
the raw kernel image may overlap.

The patch fixes the behavior by loading the kernel image once with
load_elf/load_uimage and skips loading the raw image.

When here do not use bios_name/size for the kernel and use a more generic
name called payload_name/size.

New in v3: dtb must be stored between kernel and initrd because Linux can
handle the dtb only within the first 64MB. Add a comment to
clarify the behavior.

Signed-off-by: David Engraf 


Sorry I've taken so long to reply to this.  It looks fine to me,
however, other changes mean it longer quite applies to the
ppc-for-2.12 tree.  Can you fix that up and repost please.


What other changes do you mean? In v3 I just restored the old behavior 
by putting the dtb right after the kernel image. This behavior has been 
changed by mistake in v1/v2. v3 now uses the correct storage location again.


Best regards
- David




Reviewed-by: David Gibson 


---
  hw/ppc/e500.c | 116 +++---
  1 file changed, 70 insertions(+), 46 deletions(-)

diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
index c4fe06ea2a..414c4beaab 100644
--- a/hw/ppc/e500.c
+++ b/hw/ppc/e500.c
@@ -784,8 +784,10 @@ void ppce500_init(MachineState *machine, PPCE500Params 
*params)
  int initrd_size = 0;
  hwaddr cur_base = 0;
  char *filename;
+const char *payload_name;
+bool kernel_as_payload;
  hwaddr bios_entry = 0;
-target_long bios_size;
+target_long payload_size;
  struct boot_info *boot_info;
  int dt_size;
  int i;
@@ -913,11 +915,6 @@ void ppce500_init(MachineState *machine, PPCE500Params 
*params)
  /* Register spinning region */
  sysbus_create_simple("e500-spin", params->spin_base, NULL);
  
-if (cur_base < (32 * 1024 * 1024)) {

-/* u-boot occupies memory up to 32MB, so load blobs above */
-cur_base = (32 * 1024 * 1024);
-}
-
  if (params->has_mpc8xxx_gpio) {
  qemu_irq poweroff_irq;
  
@@ -952,8 +949,61 @@ void ppce500_init(MachineState *machine, PPCE500Params *params)

  sysbus_mmio_get_region(s, 0));
  }
  
-/* Load kernel. */

-if (machine->kernel_filename) {
+/*
+ * Smart firmware defaults ahead!
+ *
+ * We follow the following table to select which payload we execute.
+ *
+ *  -kernel | -bios | payload
+ * -+---+-
+ * N|   Y   | u-boot
+ * N|   N   | u-boot
+ * Y|   Y   | u-boot
+ * Y|   N   | kernel
+ *
+ * This ensures backwards compatibility with how we used to expose
+ * -kernel to users but allows them to run through u-boot as well.
+ */
+kernel_as_payload = false;
+if (bios_name == NULL) {
+if (machine->kernel_filename) {
+payload_name = machine->kernel_filename;
+kernel_as_payload = true;
+} else {
+payload_name = "u-boot.e500";
+}
+} else {
+payload_name = bios_name;
+}
+
+filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, payload_name);
+
+payload_size = load_elf(filename, NULL, NULL, _entry, , NULL,
+1, PPC_ELF_MACHINE, 0, 0);
+if (payload_size < 0) {
+/*
+ * Hrm. No ELF image? Try a uImage, maybe someone is giving us an
+ * ePAPR compliant kernel
+ */
+payload_size = load_uimage(filename, _entry, , NULL,
+   NULL, NULL);
+if (payload_size < 0) {
+fprintf(stderr, "qemu: could not load firmware '%s'\n", filename);
+exit(1);
+}
+}
+
+g_free(filename);
+
+if (kernel_as_payload) {
+kernel_base = loadaddr;
+kernel_size = payload_size;
+}
+
+cur_base = loadaddr + payload_size;
+
+/* Load bare kernel only if no bios/u-boot has been provided */
+if (machine->kernel_filename && !kernel_as_payload) {
  kernel_base = cur_base;
  kernel_size = load_image_targphys(machine->kernel_filename,
cur_base,
@@ -967,6 +1017,11 @@ void ppce500_init(MachineState *machine, PPCE500Params 
*params)
  cur_base += kernel_size;
  }
  
+if (cur_base < (32 * 1024 * 1024)) {

+/* u-boot occupies memory up to 32MB, so load blobs above */
+cur_base = (32 * 1024 * 1024);
+}
+
  /* Load initrd. */
  if (machine->initrd_filename) {
  initrd_base = (cur_base + 

Re: [Qemu-devel] [PATCH v3] PPC: e500: Fix duplicate kernel load and device tree overlap

[David Gibson]

On Thu, Feb 15, 2018 at 10:36:00AM +0100, David Engraf wrote:
> This patch fixes an incorrect behavior when the -kernel argument has been
> specified without -bios. In this case the kernel was loaded twice. At address
> 32M as a raw image and afterwards by load_elf/load_uimage at the
> corresponding load address. In this case the region for the device tree and
> the raw kernel image may overlap.
> 
> The patch fixes the behavior by loading the kernel image once with
> load_elf/load_uimage and skips loading the raw image.
> 
> When here do not use bios_name/size for the kernel and use a more generic
> name called payload_name/size.
> 
> New in v3: dtb must be stored between kernel and initrd because Linux can
>handle the dtb only within the first 64MB. Add a comment to
>clarify the behavior.
> 
> Signed-off-by: David Engraf 

Sorry I've taken so long to reply to this.  It looks fine to me,
however, other changes mean it longer quite applies to the
ppc-for-2.12 tree.  Can you fix that up and repost please.

Reviewed-by: David Gibson 

> ---
>  hw/ppc/e500.c | 116 
> +++---
>  1 file changed, 70 insertions(+), 46 deletions(-)
> 
> diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
> index c4fe06ea2a..414c4beaab 100644
> --- a/hw/ppc/e500.c
> +++ b/hw/ppc/e500.c
> @@ -784,8 +784,10 @@ void ppce500_init(MachineState *machine, PPCE500Params 
> *params)
>  int initrd_size = 0;
>  hwaddr cur_base = 0;
>  char *filename;
> +const char *payload_name;
> +bool kernel_as_payload;
>  hwaddr bios_entry = 0;
> -target_long bios_size;
> +target_long payload_size;
>  struct boot_info *boot_info;
>  int dt_size;
>  int i;
> @@ -913,11 +915,6 @@ void ppce500_init(MachineState *machine, PPCE500Params 
> *params)
>  /* Register spinning region */
>  sysbus_create_simple("e500-spin", params->spin_base, NULL);
>  
> -if (cur_base < (32 * 1024 * 1024)) {
> -/* u-boot occupies memory up to 32MB, so load blobs above */
> -cur_base = (32 * 1024 * 1024);
> -}
> -
>  if (params->has_mpc8xxx_gpio) {
>  qemu_irq poweroff_irq;
>  
> @@ -952,8 +949,61 @@ void ppce500_init(MachineState *machine, PPCE500Params 
> *params)
>  sysbus_mmio_get_region(s, 0));
>  }
>  
> -/* Load kernel. */
> -if (machine->kernel_filename) {
> +/*
> + * Smart firmware defaults ahead!
> + *
> + * We follow the following table to select which payload we execute.
> + *
> + *  -kernel | -bios | payload
> + * -+---+-
> + * N|   Y   | u-boot
> + * N|   N   | u-boot
> + * Y|   Y   | u-boot
> + * Y|   N   | kernel
> + *
> + * This ensures backwards compatibility with how we used to expose
> + * -kernel to users but allows them to run through u-boot as well.
> + */
> +kernel_as_payload = false;
> +if (bios_name == NULL) {
> +if (machine->kernel_filename) {
> +payload_name = machine->kernel_filename;
> +kernel_as_payload = true;
> +} else {
> +payload_name = "u-boot.e500";
> +}
> +} else {
> +payload_name = bios_name;
> +}
> +
> +filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, payload_name);
> +
> +payload_size = load_elf(filename, NULL, NULL, _entry, , 
> NULL,
> +1, PPC_ELF_MACHINE, 0, 0);
> +if (payload_size < 0) {
> +/*
> + * Hrm. No ELF image? Try a uImage, maybe someone is giving us an
> + * ePAPR compliant kernel
> + */
> +payload_size = load_uimage(filename, _entry, , NULL,
> +   NULL, NULL);
> +if (payload_size < 0) {
> +fprintf(stderr, "qemu: could not load firmware '%s'\n", 
> filename);
> +exit(1);
> +}
> +}
> +
> +g_free(filename);
> +
> +if (kernel_as_payload) {
> +kernel_base = loadaddr;
> +kernel_size = payload_size;
> +}
> +
> +cur_base = loadaddr + payload_size;
> +
> +/* Load bare kernel only if no bios/u-boot has been provided */
> +if (machine->kernel_filename && !kernel_as_payload) {
>  kernel_base = cur_base;
>  kernel_size = load_image_targphys(machine->kernel_filename,
>cur_base,
> @@ -967,6 +1017,11 @@ void ppce500_init(MachineState *machine, PPCE500Params 
> *params)
>  cur_base += kernel_size;
>  }
>  
> +if (cur_base < (32 * 1024 * 1024)) {
> +/* u-boot occupies memory up to 32MB, so load blobs above */
> +cur_base = (32 * 1024 * 1024);
> +}
> +
>  /* Load initrd. */
>  if (machine->initrd_filename) {
>  initrd_base = (cur_base + INITRD_LOAD_PAD) & ~INITRD_PAD_MASK;
> @@ -983,47 +1038,16 @@ void