On Tuesday, April 8th, 2025 at 9:07 AM, Alejandro Vallejo <agarc...@amd.com>
wrote:
>
>
> From: "Daniel P. Smith" dpsm...@apertussolutions.com
>
>
> Add support to read the command line from the hyperlauunch device tree.
> The device tree command line is located in the "bootargs" property of the
> "multiboot,kernel" node.
>
> A boot loader command line, e.g. a grub module string field, takes
> precendence ove the device tree one since it is easier to modify.
>
> Signed-off-by: Daniel P. Smith dpsm...@apertussolutions.com
>
> Signed-off-by: Jason Andryuk jason.andr...@amd.com
>
> ---
> v3:
> * Rename to fdt_get_prop_offset()
> * Remove size_t cast from builder_get_cmdline_size()
> * fdt_get_prop_offset() use strcmp()
> * fdt_get_prop_offset() return bool
> ---
> xen/arch/x86/domain-builder/core.c | 28 +++++++++++++++++++++++
> xen/arch/x86/domain-builder/fdt.c | 6 +++++
> xen/arch/x86/domain-builder/fdt.h | 25 ++++++++++++++++++++
> xen/arch/x86/include/asm/bootinfo.h | 6 +++--
> xen/arch/x86/include/asm/domain-builder.h | 4 ++++
> xen/arch/x86/setup.c | 12 +++++++---
> xen/include/xen/libfdt/libfdt-xen.h | 23 +++++++++++++++++++
> 7 files changed, 99 insertions(+), 5 deletions(-)
>
> diff --git a/xen/arch/x86/domain-builder/core.c
> b/xen/arch/x86/domain-builder/core.c
> index eda7fa7a8f..510a74a675 100644
> --- a/xen/arch/x86/domain-builder/core.c
> +++ b/xen/arch/x86/domain-builder/core.c
> @@ -8,9 +8,37 @@
> #include <xen/lib.h>
>
>
> #include <asm/bootinfo.h>
>
> +#include <asm/setup.h>
>
>
> #include "fdt.h"
>
> +size_t __init builder_get_cmdline_size(struct boot_info *bi, int offset)
> +{
> +#ifdef CONFIG_DOMAIN_BUILDER
> + const void *fdt = bootstrap_map_bm(&bi->mods[HYPERLAUNCH_MODULE_IDX]);
>
> + int size = fdt_cmdline_prop_size(fdt, offset);
> +
> + bootstrap_unmap();
> + return size < 0 ? 0 : size;
> +#else
> + return 0;
> +#endif
> +}
> +
> +int __init builder_get_cmdline(
> + struct boot_info *bi, int offset, char *cmdline, size_t size)
> +{
> +#ifdef CONFIG_DOMAIN_BUILDER
> + const void *fdt = bootstrap_map_bm(&bi->mods[HYPERLAUNCH_MODULE_IDX]);
>
> + int ret = fdt_cmdline_prop_copy(fdt, offset, cmdline, size);
> +
> + bootstrap_unmap();
> + return ret;
> +#else
> + return 0;
> +#endif
> +}
> +
> void __init builder_init(struct boot_info *bi)
> {
> if ( IS_ENABLED(CONFIG_DOMAIN_BUILDER) )
> diff --git a/xen/arch/x86/domain-builder/fdt.c
> b/xen/arch/x86/domain-builder/fdt.c
> index a037c8b6cb..bc9903a9de 100644
> --- a/xen/arch/x86/domain-builder/fdt.c
> +++ b/xen/arch/x86/domain-builder/fdt.c
> @@ -189,6 +189,12 @@ static int __init process_domain_node(
> printk(" kernel: boot module %d\n", idx);
> bi->mods[idx].type = BOOTMOD_KERNEL;
>
> bd->kernel = &bi->mods[idx];
>
> +
> + /* If bootloader didn't set cmdline, see if FDT provides one. */
> + if ( bd->kernel->cmdline_pa &&
>
> + !((char *)__va(bd->kernel->cmdline_pa))[0] )
>
> + bd->kernel->fdt_cmdline = fdt_get_prop_offset(
>
> + fdt, node, "bootargs", &bd->kernel->cmdline_pa);
>
> }
> }
>
> diff --git a/xen/arch/x86/domain-builder/fdt.h
> b/xen/arch/x86/domain-builder/fdt.h
> index e8769dc51c..91f665c8fd 100644
> --- a/xen/arch/x86/domain-builder/fdt.h
> +++ b/xen/arch/x86/domain-builder/fdt.h
> @@ -12,6 +12,31 @@ struct boot_info;
> #define HYPERLAUNCH_MODULE_IDX 0
>
> #ifdef CONFIG_DOMAIN_BUILDER
> +
> +static inline int __init fdt_cmdline_prop_size(const void *fdt, int offset)
> +{
> + int ret;
> +
> + fdt_get_property_by_offset(fdt, offset, &ret);
> +
> + return ret;
> +}
> +
> +static inline int __init fdt_cmdline_prop_copy(
> + const void *fdt, int offset, char *cmdline, size_t size)
> +{
> + int ret;
> + const struct fdt_property *prop =
> + fdt_get_property_by_offset(fdt, offset, &ret);
> +
> + if ( ret < 0 )
> + return ret;
> +
> + ASSERT(size > ret);
>
> +
> + return strlcpy(cmdline, prop->data, ret);
>
> +}
> +
> int has_hyperlaunch_fdt(const struct boot_info *bi);
> int walk_hyperlaunch_fdt(struct boot_info bi);
> #else
> diff --git a/xen/arch/x86/include/asm/bootinfo.h
> b/xen/arch/x86/include/asm/bootinfo.h
> index 1e3d582e45..5b2c93b1ef 100644
> --- a/xen/arch/x86/include/asm/bootinfo.h
> +++ b/xen/arch/x86/include/asm/bootinfo.h
> @@ -35,11 +35,13 @@ struct boot_module {
>
> /
> * Module State Flags:
> - * relocated: indicates module has been relocated in memory.
> - * released: indicates module's pages have been freed.
> + * relocated: indicates module has been relocated in memory.
> + * released: indicates module's pages have been freed.
> + * fdt_cmdline: indicates module's cmdline is in the FDT.
> /
> bool relocated:1;
> bool released:1;
> + bool fdt_cmdline:1;
>
> /
> * A boot module may need decompressing by Xen. Headroom is an estimate of
> diff --git a/xen/arch/x86/include/asm/domain-builder.h
> b/xen/arch/x86/include/asm/domain-builder.h
> index b6d9ba94de..7518b6ddf3 100644
> --- a/xen/arch/x86/include/asm/domain-builder.h
> +++ b/xen/arch/x86/include/asm/domain-builder.h
> @@ -3,6 +3,10 @@
>
> struct boot_info;
>
> +size_t __init builder_get_cmdline_size(struct boot_info *bi, int offset);
> +int __init builder_get_cmdline(
> + struct boot_info *bi, int offset, char *cmdline, size_t size);
> +
> void builder_init(struct boot_info *bi);
>
> #endif
> diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
> index 00e8c8a2a3..ca4415d020 100644
> --- a/xen/arch/x86/setup.c
> +++ b/xen/arch/x86/setup.c
> @@ -984,7 +984,10 @@ static size_t __init domain_cmdline_size(
> {
> size_t s = bi->kextra ? strlen(bi->kextra) : 0;
>
>
> - s += bd->kernel->cmdline_pa ? strlen(__va(bd->kernel->cmdline_pa)) : 0;
>
> + if ( bd->kernel->fdt_cmdline )
>
> + s += builder_get_cmdline_size(bi, bd->kernel->cmdline_pa);
>
> + else
> + s += strlen(__va(bd->kernel->cmdline_pa));
>
>
> if ( s == 0 )
> return s;
> @@ -1047,9 +1050,12 @@ static struct domain *__init create_dom0(struct
> boot_info *bi)
> if ( !(cmdline = xzalloc_array(char, cmdline_size)) )
> panic("Error allocating cmdline buffer for %pd\n", d);
>
> - if ( bd->kernel->cmdline_pa )
>
> + if ( bd->kernel->fdt_cmdline )
>
> + builder_get_cmdline(
> + bi, bd->kernel->cmdline_pa, cmdline, cmdline_size);
>
> + else
> strlcpy(cmdline,
> - cmdline_cook(__va(bd->kernel->cmdline_pa), bi->loader),
>
> + cmdline_cook(__va(bd->kernel->cmdline_pa),bi->loader),
Add extra space before bi->loader?
>
> cmdline_size);
>
> if ( bi->kextra )
>
> diff --git a/xen/include/xen/libfdt/libfdt-xen.h
> b/xen/include/xen/libfdt/libfdt-xen.h
> index 2259c09a6a..e473fbaf0c 100644
> --- a/xen/include/xen/libfdt/libfdt-xen.h
> +++ b/xen/include/xen/libfdt/libfdt-xen.h
> @@ -23,6 +23,29 @@ static inline uint64_t __init fdt_cell_as_u64(const
> fdt32_t *cell)
> return ((uint64_t)fdt32_to_cpu(cell[0]) << 32) | fdt32_to_cpu(cell[1]);
> }
>
> +static inline bool __init fdt_get_prop_offset(
> + const void *fdt, int node, const char *name, unsigned long *offset)
> +{
> + int ret, poffset;
> + const char *pname;
> +
> + fdt_for_each_property_offset(poffset, fdt, node)
> + {
> + fdt_getprop_by_offset(fdt, poffset, &pname, &ret);
Return value is not checked.
> +
> + if ( ret < 0 )
> + continue;
> +
> + if ( strcmp(pname, name) == 0 )
I got an impression that the preferred form is
if ( !strcmp(pname, name) )
> + {
> + offset = poffset;
> + return true;
> + }
> + }
> +
> + return false;
> +}
> +
> /
> * Property: reg
> *
> --
> 2.43.0
