Re: [Minios-devel] [UNIKRAFT PATCHv5 36/46] plat/kvm: Parse memory info from device tree for Arm64

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

On 10.08.2018 09:08, Wei Chen wrote:
> From: Wei Chen <Wei.Chen@xxxxxxx>
>
> QEMU/KVM will store the memory informations like memory
> region, memory base address and memory size to device
> tree. We parse these informations for memory allocater and
> new stack setting. QEMU/KVM will always provide us at least
> one bank of memory and unikraft will use the first bank for
> the time-being. So currently we only supported one bank.
>
> Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
> ---
>   plat/kvm/arm/setup.c | 76 ++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 76 insertions(+)
>
> diff --git a/plat/kvm/arm/setup.c b/plat/kvm/arm/setup.c
> index d59956a..a74c85f 100644
> --- a/plat/kvm/arm/setup.c
> +++ b/plat/kvm/arm/setup.c
> @@ -21,7 +21,13 @@
>   #include <libfdt.h>
>   #include <kvm/console.h>
>   #include <uk/assert.h>
> +#include <mm.h>
> +#include <uk/arch/limits.h>
>   
> +void *_libkvmplat_pagetable;
> +void *_libkvmplat_heap_start;
> +void *_libkvmplat_stack_top;
> +void *_libkvmplat_mem_end;
>   void *_libkvmplat_dtb;
>   
>   #define MAX_CMDLINE_SIZE 1024
> @@ -38,6 +44,68 @@ static void _init_dtb(void *dtb_pointer)
>         uk_printd(DLVL_INFO, "Found device tree on: %p\n", dtb_pointer);
>   }
>   
> +static void _init_dtb_mem(void)
> +{
> +       extern char _text[];
> +       extern char _end[];
> +       int fdt_mem, prop_len = 0, prop_min_len;
> +       int naddr, nsize;
> +       const uint64_t *regs;
> +       uint64_t mem_base, mem_size, max_addr;
> +
> +       /* search for assigned VM memory in DTB */
> +       if (fdt_num_mem_rsv(_libkvmplat_dtb) != 0)
> +               uk_printd(DLVL_WARN, "Reserved memory is not supported\n");
> +
> +       fdt_mem = fdt_node_offset_by_prop_value(_libkvmplat_dtb, -1,
> +                                               "device_type",
> +                                               "memory", sizeof("memory"));
> +       if (fdt_mem < 0) {
> +               uk_printd(DLVL_WARN, "No memory found in DTB\n");
> +               return;
> +       }
> +
> +       naddr = fdt_address_cells(_libkvmplat_dtb, fdt_mem);
> +       if (naddr < 0 || naddr >= FDT_MAX_NCELLS)
> +               UK_CRASH("Could not find proper address cells!\n");
> +
> +       nsize = fdt_size_cells(_libkvmplat_dtb, fdt_mem);
> +       if (nsize < 0 || nsize >= FDT_MAX_NCELLS)
> +               UK_CRASH("Could not find proper size cells!\n");
> +
> +       /*
> +        * QEMU will always provide us at least one bank of memory.
> +        * unikraft will use the first bank for the time-being.
> +        */
> +       regs = fdt_getprop(_libkvmplat_dtb, fdt_mem, "reg", &prop_len);
> +
> +       /*
> +        * The property must contain at least the start address
> +        * and size, each of which is 8-bytes.
> +        */
> +       prop_min_len = (int)sizeof(fdt32_t) * (naddr + nsize);
> +       if (regs == NULL || prop_len < prop_min_len)
> +               UK_CRASH("Bad 'reg' property: %p %d\n", regs, prop_len);
> +
> +       /* If we have more than one memory bank, give a warning messasge */
> +       if (prop_len > prop_min_len)
> +               uk_printd(DLVL_WARN,
> +                       "Currently, we support only one memory bank!\n");
> +
> +       mem_base = fdt64_to_cpu(regs[0]);
> +       mem_size = fdt64_to_cpu(regs[1]);
> +       if (mem_base > (uint64_t)&_text)
> +               UK_CRASH("Fatal: Image outside of RAM\n");
> +
> +       max_addr = mem_base + mem_size;
> +       _libkvmplat_pagetable =(void *) ALIGN_UP((size_t)&_end, __PAGE_SIZE);
> +       _libkvmplat_heap_start = _libkvmplat_pagetable + PAGE_TABLE_SIZE;
> +       _libkvmplat_mem_end = (void *) max_addr;
> +
> +       /* AArch64 require stack be 16-bytes alignment by default */
> +       _libkvmplat_stack_top = (void *) ALIGN_UP(max_addr, __STACK_ALIGN_SIZE);
Shouldn't this be ALIGN_DOWN()? We may leave our RAM region, right?
> +}
> +
>   static void _dtb_get_cmdline(char *cmdline, size_t maxlen)
>   {
>         int fdtchosen, len;
> @@ -72,5 +140,13 @@ void _libkvmplat_start(void *dtb_pointer)
>         uk_printd(DLVL_INFO, "Entering from KVM (arm64)...\n");
>   
>   	/* Get command line from DTB */
> +
>         _dtb_get_cmdline(cmdline, sizeof(cmdline));
> +
> +       /* Initialize memory from DTB */
> +       _init_dtb_mem();
> +
> +       uk_printd(DLVL_INFO, "pagetable start: %p\n", _libkvmplat_pagetable);
> +       uk_printd(DLVL_INFO, "     heap start: %p\n", _libkvmplat_heap_start);
> +       uk_printd(DLVL_INFO, "      stack top: %p\n", _libkvmplat_stack_top);
>   }
_______________________________________________
Minios-devel mailing list
Minios-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/minios-devel