Re: [PATCH 12/22] KVM: MMU: Implement nested gva_to_gpa functions

Avi Kivity
2010-04-27T12:37:42Z

On 04/27/2010 01:38 PM, Joerg Roedel wrote:
> This patch adds the functions to do a nested l2_gva to
> l1_gpa page table walk.
>
> Signed-off-by: Joerg Roedel<joerg.roedel@amd.com>
> ---
> arch/x86/include/asm/kvm_host.h | 4 ++++
> arch/x86/kvm/mmu.c | 8 ++++++++
> arch/x86/kvm/paging_tmpl.h | 31 +++++++++++++++++++++++++++++++
> 3 files changed, 43 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index ccdbd2f..3cbfb51 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -287,6 +287,10 @@ struct kvm_vcpu_arch {
> bool tpr_access_reporting;
>
> struct kvm_mmu mmu;
> +
> + /* Used for two dimensional paging emulation */
> + struct kvm_mmu nested_mmu;
> +
> /* only needed in kvm_pv_mmu_op() path, but it's hot so
> * put it here to avoid allocation */
> struct kvm_pv_mmu_op_buffer mmu_op_buffer;
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 4e0bfdb..8bd40b5 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2144,6 +2144,14 @@ static gpa_t nonpaging_gva_to_gpa(struct kvm_vcpu *vcpu, gva_t vaddr,
> return vaddr;
> }
>
> +static gpa_t nonpaging_gva_to_gpa_nested(struct kvm_vcpu *vcpu, gva_t vaddr,
> + u32 access, u32 *error)
> +{
> + if (error)
> + *error = 0;
>

Why allow error == NULL?

>
> +static gpa_t FNAME(gva_to_gpa_nested)(struct kvm_vcpu *vcpu, gva_t vaddr,
> + u32 access, u32 *error)
> +{
> + struct guest_walker walker;
> + gpa_t gpa = UNMAPPED_GVA;
> + int r;
> +
> + r = FNAME(walk_addr_nested)(&walker, vcpu, vaddr,
> + !!(access& PFERR_WRITE_MASK),
> + !!(access& PFERR_USER_MASK),
> + !!(access& PFERR_FETCH_MASK));
>

Those !! are unneeded.

--
error compiling committee.c: too many arguments to function