Re: [Xen-devel] [PATCH, v2] linux-2.6.18: add privileged/unprivileged kernel feature indication

[Keir Fraser <keir@xxxxxxx>]

Aren't XEN_PRIV_CAP_STR parts pointless? Any hypervisor new enough to
understand those features will also understand
XEN_ELFNOTE_SUPPORTED_FEATURE?

 -- Keir

On 19/07/2011 10:14, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

> This is the kernel side change accompanying the earlier sent Xen side
> patch titled identically.
> 
> (This depends on the public headers to be synced over after the
> respective hypervisor side change.)
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
> 
> --- a/arch/i386/kernel/head-xen.S
> +++ b/arch/i386/kernel/head-xen.S
> @@ -12,6 +12,7 @@
>  #include <asm/dwarf2.h>
>  #include <xen/interface/xen.h>
>  #include <xen/interface/elfnote.h>
> +#include <xen/interface/features.h>
>  
>  /*
>   * References to members of the new_cpu_data structure.
> @@ -142,6 +143,19 @@ ENTRY(cpu_gdt_table)
> .quad 0x0000000000000000 /* 0xf0 - unused */
> .quad 0x0000000000000000 /* 0xf8 - GDT entry 31: double-fault TSS */
>  
> +#ifdef CONFIG_XEN_UNPRIVILEGED_GUEST
> +# define XEN_PRIV_CAP  (1 << XENFEAT_unprivileged)
> +# define XEN_PRIV_CAP_STR "|!unprivileged"
> +#else
> +# define XEN_PRIV_CAP  ((1 << XENFEAT_privileged) | \
> +    (1 << XENFEAT_unprivileged))
> +# define XEN_PRIV_CAP_STR "|privileged|unprivileged"
> +#endif
> +#if CONFIG_XEN_COMPAT < 0xffffffff//temp 0x040200
> +# undef XEN_PRIV_CAP_STR
> +# define XEN_PRIV_CAP_STR ""
> +#endif
> +
>  #if CONFIG_XEN_COMPAT <= 0x030002
>  /*
>   * __xen_guest information
> @@ -168,7 +182,8 @@ ENTRY(cpu_gdt_table)
> utoa (__PAGE_OFFSET + __PHYSICAL_START + VIRT_ENTRY_OFFSET)
> .ascii ",HYPERCALL_PAGE=0x"
> utoa ((__PHYSICAL_START+HYPERCALL_PAGE_OFFSET)>>PAGE_SHIFT)
> - .ascii  ",FEATURES=writable_page_tables"
> + .ascii  ",FEATURES=" XEN_PRIV_CAP
> + .ascii          "|writable_page_tables"
> .ascii          "|writable_descriptor_tables"
> .ascii          "|auto_translated_physmap"
> .ascii          "|pae_pgdir_above_4gb"
> @@ -195,7 +210,18 @@ ENTRY(cpu_gdt_table)
> ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .long,  startup_32)
> ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .long,  hypercall_page)
> ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW,   .long,  HYPERVISOR_VIRT_START)
> - ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz,
> "writable_page_tables|writable_descriptor_tables|auto_translated_physmap|pae_p
> gdir_above_4gb|supervisor_mode_kernel")
> + ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii, "writable_page_tables";
> +       .ascii  "|writable_descriptor_tables";
> +       .ascii  "|auto_translated_physmap";
> +       .ascii  "|pae_pgdir_above_4gb";
> +       .ascii  "|supervisor_mode_kernel";
> +       .asciz  XEN_PRIV_CAP_STR)
> + ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES, .long, XEN_PRIV_CAP |
> +        (1 << XENFEAT_writable_page_tables) |
> +        (1 << XENFEAT_writable_descriptor_tables) |
> +        (1 << XENFEAT_auto_translated_physmap) |
> +        (1 << XENFEAT_pae_pgdir_above_4gb) |
> +        (1 << XENFEAT_supervisor_mode_kernel))
>  #ifdef CONFIG_X86_PAE
> ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz, "yes")
> ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,   .quad,  _PAGE_PRESENT,_PAGE_PRESENT)
> --- a/arch/x86_64/kernel/head-xen.S
> +++ b/arch/x86_64/kernel/head-xen.S
> @@ -24,6 +24,7 @@
>  #include <asm/cache.h>
>  #include <asm/dwarf2.h>
>  #include <xen/interface/elfnote.h>
> +#include <xen/interface/features.h>
>  
> .section .bootstrap.text, "ax", @progbits
> .code64
> @@ -160,6 +161,19 @@ gdt_end:
>  ENTRY(empty_zero_page)
> .skip PAGE_SIZE
>  
> +#ifdef CONFIG_XEN_UNPRIVILEGED_GUEST
> +# define XEN_PRIV_CAP  (1 << XENFEAT_unprivileged)
> +# define XEN_PRIV_CAP_STR "|!unprivileged"
> +#else
> +# define XEN_PRIV_CAP  ((1 << XENFEAT_privileged) | \
> +    (1 << XENFEAT_unprivileged))
> +# define XEN_PRIV_CAP_STR "|privileged|unprivileged"
> +#endif
> +#if CONFIG_XEN_COMPAT < 0xffffffff//temp 0x040200
> +# undef XEN_PRIV_CAP_STR
> +# define XEN_PRIV_CAP_STR ""
> +#endif
> +
>  #if CONFIG_XEN_COMPAT <= 0x030002
>  /*
>   * __xen_guest information
> @@ -186,7 +200,8 @@ ENTRY(empty_zero_page)
> utoh (__START_KERNEL_map + __PHYSICAL_START)
> .ascii ",HYPERCALL_PAGE=0x"
> utoh (phys_hypercall_page >> PAGE_SHIFT)
> - .ascii  ",FEATURES=writable_page_tables"
> + .ascii  ",FEATURES=" XEN_PRIV_CAP
> + .ascii   "|writable_page_tables"
> .ascii   "|writable_descriptor_tables"
> .ascii   "|auto_translated_physmap"
> .ascii          "|supervisor_mode_kernel"
> @@ -206,6 +221,15 @@ ENTRY(empty_zero_page)
> ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .quad,  startup_64)
> ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .quad,  hypercall_page)
> ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,   .quad,  _PAGE_PRESENT,_PAGE_PRESENT)
> - ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz,
> "writable_page_tables|writable_descriptor_tables|auto_translated_physmap|super
> visor_mode_kernel")
> + ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .ascii, "writable_page_tables";
> +       .ascii  "|writable_descriptor_tables";
> +       .ascii  "|auto_translated_physmap";
> +       .ascii  "|supervisor_mode_kernel";
> +       .asciz  XEN_PRIV_CAP_STR)
> + ELFNOTE(Xen, XEN_ELFNOTE_SUPPORTED_FEATURES, .long, XEN_PRIV_CAP |
> +        (1 << XENFEAT_writable_page_tables) |
> +        (1 << XENFEAT_writable_descriptor_tables) |
> +        (1 << XENFEAT_auto_translated_physmap) |
> +        (1 << XENFEAT_supervisor_mode_kernel))
> ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz, "generic")
> ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long,  1)
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel



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