Re: [Xen-devel] Configuration of nestedhvm

[Christoph Egger <Christoph.Egger@xxxxxxx>]

Eddie,

you can simplify the second patch with attached patch merged
and is correct for AMD side.

Signed-off-by: Christoph Egger <Christoph.Egger@xxxxxxx>

Christoph


On Friday 08 October 2010 06:34:14 Dong, Eddie wrote:
> Keir:
>        Despite of the negotioatiom of nested virtualization wrapper, here
> comes with the global configuration parameter and the CR4 layout handling
> between SVM & VMX. These are wrapper neutral IMO.
>
> Thx, Eddie
>
>
>
> ===Patch1
>
> Nested virtualization usage model is emerging, however we must guarantee it
> won't impact the performance of simple virtualization. This patch add an
> boot parameter for nested virtualization, which is disabled by default for
> now.
>
> Signed-off-by: Eddie Dong <eddie.dong@xxxxxxxxx>
>
>
> diff -r 1385b15e168f xen/arch/x86/hvm/hvm.c
> --- a/xen/arch/x86/hvm/hvm.c  Wed Oct 06 17:38:15 2010 +0100
> +++ b/xen/arch/x86/hvm/hvm.c  Fri Oct 08 10:29:38 2010 +0800
> @@ -66,6 +66,9 @@ unsigned int opt_hvm_debug_level __read_
>  unsigned int opt_hvm_debug_level __read_mostly;
>  integer_param("hvm_debug", opt_hvm_debug_level);
>
> +unsigned int enable_nested_hvm __read_mostly;
> +integer_param("nested_hvm", enable_nested_hvm);
> +
>  struct hvm_function_table hvm_funcs __read_mostly;
>
>  /* I/O permission bitmap is globally shared by all HVM guests. */
> diff -r 1385b15e168f xen/include/asm-x86/hvm/hvm.h
> --- a/xen/include/asm-x86/hvm/hvm.h   Wed Oct 06 17:38:15 2010 +0100
> +++ b/xen/include/asm-x86/hvm/hvm.h   Fri Oct 08 10:35:03 2010 +0800
> @@ -250,6 +250,9 @@ hvm_set_segment_register(struct vcpu *v,
>  #define is_viridian_domain(_d)                                            
> \ (is_hvm_domain(_d) && ((_d)->arch.hvm_domain.params[HVM_PARAM_VIRIDIAN]))
>
> +/* TODO: handle per domain configuration */
> +#define is_nestedhvm(_d)     (enable_nested_hvm && is_hvm_domain(_d))
> +
>  void hvm_cpuid(unsigned int input, unsigned int *eax, unsigned int *ebx,
>                                     unsigned int *ecx, unsigned int *edx);
>  void hvm_migrate_timers(struct vcpu *v);
>
>
> ===Patch2
>
> This patch solves the CR4 bit (VMXE) format difference between AMD & Intel
> processor.
>
> Signed-off-by: Qing He <qing.he@xxxxxxxxx>
> Signed-off-by: Eddie Dong <eddie.dong@xxxxxxxxx>
>
> diff -r 1385b15e168f xen/arch/x86/hvm/hvm.c
> --- a/xen/arch/x86/hvm/hvm.c  Wed Oct 06 17:38:15 2010 +0100
> +++ b/xen/arch/x86/hvm/hvm.c  Fri Oct 08 10:46:55 2010 +0800
> @@ -630,6 +630,11 @@ static int hvm_load_cpu_ctxt(struct doma
>      struct hvm_hw_cpu ctxt;
>      struct segment_register seg;
>      struct vcpu_guest_context *vc;
> +    unsigned long rsv_bits = HVM_CR4_GUEST_RESERVED_BITS;
> +
> +    if ( !is_nestedhvm(d) ||
> +          boot_cpu_data.x86_vendor == X86_VENDOR_AMD )
> +        rsv_bits |= X86_CR4_VMXE;
>
>      /* Which vcpu is this? */
>      vcpuid = hvm_load_instance(h);
> @@ -662,7 +667,7 @@ static int hvm_load_cpu_ctxt(struct doma
>          return -EINVAL;
>      }
>
> -    if ( ctxt.cr4 & HVM_CR4_GUEST_RESERVED_BITS )
> +    if ( ctxt.cr4 & rsv_bits )
>      {
>          gdprintk(XENLOG_ERR, "HVM restore: bad CR4 0x%"PRIx64"\n",
>                   ctxt.cr4);
> @@ -1243,8 +1248,12 @@ int hvm_set_cr4(unsigned long value)
>  {
>      struct vcpu *v = current;
>      unsigned long old_cr;
> -
> -    if ( value & HVM_CR4_GUEST_RESERVED_BITS )
> +    unsigned long rsv_bits = HVM_CR4_GUEST_RESERVED_BITS;
> +
> +    if ( !is_nestedhvm(v->domain) ||
> +         boot_cpu_data.x86_vendor == X86_VENDOR_AMD )
> +        rsv_bits |= X86_CR4_VMXE;
> +    if ( value & rsv_bits )
>      {
>          HVM_DBG_LOG(DBG_LEVEL_1,
>                      "Guest attempts to set reserved bit in CR4: %lx",
> diff -r 1385b15e168f xen/include/asm-x86/hvm/hvm.h
> --- a/xen/include/asm-x86/hvm/hvm.h   Wed Oct 06 17:38:15 2010 +0100
> +++ b/xen/include/asm-x86/hvm/hvm.h   Fri Oct 08 10:46:35 2010 +0800
> @@ -291,7 +291,8 @@ static inline int hvm_do_pmu_interrupt(s
>          X86_CR4_DE  | X86_CR4_PSE | X86_CR4_PAE |       \
>          X86_CR4_MCE | X86_CR4_PGE | X86_CR4_PCE |       \
>          X86_CR4_OSFXSR | X86_CR4_OSXMMEXCPT |           \
> -        (cpu_has_xsave ? X86_CR4_OSXSAVE : 0))))
> +        (cpu_has_xsave ? X86_CR4_OSXSAVE : 0))) |       \
> +        X86_CR4_VMXE)
>
>  /* These exceptions must always be intercepted. */
>  #define HVM_TRAP_MASK ((1U << TRAP_machine_check) | (1U <<
> TRAP_invalid_op))



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Attachment: xen_vmx_enable.diff
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