On Thu, Sep 26, 2019 at 04:17:57PM -0700, Ben Gardon wrote:
> Separate the functions for generating MMIO page table entries from the
> function that inserts them into the paging structure. This refactoring
> will allow changes to the MMU sychronization model to use atomic
> compare / exchanges (which are not guaranteed to succeed) instead of a
> monolithic MMU lock.
>
> Signed-off-by: Ben Gardon <bgardon@xxxxxxxxxx>
> ---
> arch/x86/kvm/mmu.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 5269aa057dfa6..781c2ca7455e3 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -390,8 +390,7 @@ static u64 get_mmio_spte_generation(u64 spte)
> return gen;
> }
>
> -static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
> - unsigned access)
> +static u64 generate_mmio_pte(struct kvm_vcpu *vcpu, u64 gfn, unsigned access)
Maybe get_mmio_spte_value()? I see "generate" and all I can think of is
the generation number and nothing else.
> {
> u64 gen = kvm_vcpu_memslots(vcpu)->generation & MMIO_SPTE_GEN_MASK;
> u64 mask = generation_mmio_spte_mask(gen);
> @@ -403,6 +402,17 @@ static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
> mask |= (gpa & shadow_nonpresent_or_rsvd_mask)
> << shadow_nonpresent_or_rsvd_mask_len;
>
> + return mask;
> +}
> +
> +static void mark_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, u64 gfn,
> + unsigned access)
> +{
> + u64 mask = generate_mmio_pte(vcpu, gfn, access);
> + unsigned int gen = get_mmio_spte_generation(mask);
> +
> + access = mask & ACC_ALL;
> +
> trace_mark_mmio_spte(sptep, gfn, access, gen);
> mmu_spte_set(sptep, mask);
> }
> --
> 2.23.0.444.g18eeb5a265-goog
>
