Re: [PATCH 2/3] mini-os: prefer memory map via start_info for PVH

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>]

Juergen Gross, le sam. 18 juin 2022 12:48:15 +0200, a ecrit:
> Since some time now a guest started in PVH mode will get the memory
> map from Xen via the start_info structure.
> 
> Modify the PVH initialization to prefer this memory map over the one
> obtained via hypercall, as this will allow to add information to the
> memory map for a new kernel when supporting kexec.
> 
> In case the start_info structure doesn't contain memory map information
> fall back to the hypercall.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>

> ---
>  arch/x86/mm.c  |  6 ++++++
>  e820.c         | 25 +++++++++++++++++++++++++
>  include/e820.h |  4 ++++
>  3 files changed, 35 insertions(+)
> 
> diff --git a/arch/x86/mm.c b/arch/x86/mm.c
> index 220c0b4d..41fcee67 100644
> --- a/arch/x86/mm.c
> +++ b/arch/x86/mm.c
> @@ -45,6 +45,7 @@
>  #include <mini-os/xmalloc.h>
>  #include <mini-os/e820.h>
>  #include <xen/memory.h>
> +#include <xen/arch-x86/hvm/start_info.h>
>  
>  #ifdef MM_DEBUG
>  #define DEBUG(_f, _a...) \
> @@ -108,6 +109,11 @@ void arch_mm_preinit(void *p)
>  {
>      long ret;
>      domid_t domid = DOMID_SELF;
> +    struct hvm_start_info *hsi = p;
> +
> +    if ( hsi->version >= 1 && hsi->memmap_entries > 0 )
> +        e820_init_memmap((struct hvm_memmap_table_entry *)(unsigned long)
> +                         hsi->memmap_paddr, hsi->memmap_entries);
>  
>      pt_base = page_table_base;
>      first_free_pfn = PFN_UP(to_phys(&_end));
> diff --git a/e820.c b/e820.c
> index 991ed382..ad91e00b 100644
> --- a/e820.c
> +++ b/e820.c
> @@ -54,6 +54,7 @@ static char *e820_types[E820_TYPES] = {
>      [E820_ACPI]     = "ACPI",
>      [E820_NVS]      = "NVS",
>      [E820_UNUSABLE] = "Unusable",
> +    [E820_DISABLED] = "Disabled",
>      [E820_PMEM]     = "PMEM"
>  };
>  
> @@ -259,6 +260,30 @@ static void e820_get_memmap(void)
>      e820_sanitize();
>  }
>  
> +void e820_init_memmap(struct hvm_memmap_table_entry *entry, unsigned int num)
> +{
> +    unsigned int i;
> +
> +    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_RAM != E820_RAM);
> +    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_RESERVED != E820_RESERVED);
> +    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_ACPI != E820_ACPI);
> +    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_NVS != E820_NVS);
> +    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_UNUSABLE != E820_UNUSABLE);
> +    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_DISABLED != E820_DISABLED);
> +    BUILD_BUG_ON(XEN_HVM_MEMMAP_TYPE_PMEM != E820_PMEM);
> +
> +    for ( i = 0; i < num; i++ )
> +    {
> +        e820_map[i].addr = entry[i].addr;
> +        e820_map[i].size = entry[i].size;
> +        e820_map[i].type = entry[i].type;
> +    }
> +
> +    e820_entries = num;
> +
> +    e820_sanitize();
> +}
> +
>  void arch_print_memmap(void)
>  {
>      int i;
> diff --git a/include/e820.h b/include/e820.h
> index aaf2f2ca..5438a7c8 100644
> --- a/include/e820.h
> +++ b/include/e820.h
> @@ -26,6 +26,8 @@
>  
>  #if defined(__arm__) || defined(__aarch64__) || defined(CONFIG_PARAVIRT)
>  #define CONFIG_E820_TRIVIAL
> +#else
> +#include <xen/arch-x86/hvm/start_info.h>
>  #endif
>  
>  /* PC BIOS standard E820 types and structure. */
> @@ -34,6 +36,7 @@
>  #define E820_ACPI         3
>  #define E820_NVS          4
>  #define E820_UNUSABLE     5
> +#define E820_DISABLED     6
>  #define E820_PMEM         7
>  #define E820_TYPES        8
>  
> @@ -54,6 +57,7 @@ unsigned long e820_get_max_contig_pages(unsigned long pfn, 
> unsigned long pages);
>  #ifndef CONFIG_E820_TRIVIAL
>  unsigned long e820_get_reserved_pfns(int pages);
>  void e820_put_reserved_pfns(unsigned long start_pfn, int pages);
> +void e820_init_memmap(struct hvm_memmap_table_entry *entry, unsigned int 
> num);
>  #endif
>  
>  #endif /*__E820_HEADER*/
> -- 
> 2.35.3
> 

-- 
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.