On Mon, Jun 20, 2011 at 11:29:47PM +0900, Takuya Yoshikawa wrote:
> From: Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx>
>
> Avoid two step jump to the error handling part. This eliminates the use
> of the variables present and rsvd_fault.
>
> We also use the const type qualifier to show that write/user/fetch_fault
> do not change in the function.
>
> Both of these were suggested by Ingo Molnar.
>
> Cc: Ingo Molnar <mingo@xxxxxxx>
> Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@xxxxxxxxxxxxx>
> ---
> v2-v3: only changelog update
>
> arch/x86/kvm/paging_tmpl.h | 64 +++++++++++++++++++------------------------
> 1 files changed, 28 insertions(+), 36 deletions(-)
>
> diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
> index 1caeb4d..137aa45 100644
> --- a/arch/x86/kvm/paging_tmpl.h
> +++ b/arch/x86/kvm/paging_tmpl.h
> @@ -125,18 +125,17 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
> gfn_t table_gfn;
> unsigned index, pt_access, uninitialized_var(pte_access);
> gpa_t pte_gpa;
> - bool eperm, present, rsvd_fault;
> - int offset, write_fault, user_fault, fetch_fault;
> -
> - write_fault = access & PFERR_WRITE_MASK;
> - user_fault = access & PFERR_USER_MASK;
> - fetch_fault = access & PFERR_FETCH_MASK;
> + bool eperm;
> + int offset;
> + const int write_fault = access & PFERR_WRITE_MASK;
> + const int user_fault = access & PFERR_USER_MASK;
> + const int fetch_fault = access & PFERR_FETCH_MASK;
> + u16 errcode = 0;
>
> trace_kvm_mmu_pagetable_walk(addr, write_fault, user_fault,
> fetch_fault);
> walk:
> - present = true;
> - eperm = rsvd_fault = false;
> + eperm = false;
> walker->level = mmu->root_level;
> pte = mmu->get_cr3(vcpu);
>
> @@ -145,7 +144,7 @@ walk:
> pte = kvm_pdptr_read_mmu(vcpu, mmu, (addr >> 30) & 3);
> trace_kvm_mmu_paging_element(pte, walker->level);
> if (!is_present_gpte(pte)) {
> - present = false;
> + errcode |= PFERR_PRESENT_MASK;
> goto error;
> }
> --walker->level;
> @@ -171,34 +170,34 @@ walk:
> real_gfn = mmu->translate_gpa(vcpu, gfn_to_gpa(table_gfn),
> PFERR_USER_MASK|PFERR_WRITE_MASK);
> if (unlikely(real_gfn == UNMAPPED_GVA)) {
> - present = false;
> - break;
> + errcode |= PFERR_PRESENT_MASK;
> + goto error;
> }
> real_gfn = gpa_to_gfn(real_gfn);
>
> host_addr = gfn_to_hva(vcpu->kvm, real_gfn);
> if (unlikely(kvm_is_error_hva(host_addr))) {
> - present = false;
> - break;
> + errcode |= PFERR_PRESENT_MASK;
> + goto error;
> }
>
> ptep_user = (pt_element_t __user *)((void *)host_addr + offset);
> if (unlikely(__copy_from_user(&pte, ptep_user, sizeof(pte)))) {
> - present = false;
> - break;
> + errcode |= PFERR_PRESENT_MASK;
> + goto error;
> }
>
> trace_kvm_mmu_paging_element(pte, walker->level);
>
> if (unlikely(!is_present_gpte(pte))) {
> - present = false;
> - break;
> + errcode |= PFERR_PRESENT_MASK;
> + goto error;
> }
Assignment of PFERR_PRESENT_MASK is inverted.
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
