Re: [PATCH 05/23] KVM: MMU: pull computation of kvm_mmu_role_regs to kvm_init_mmu

David Matlack
2022-02-04T18:45:44Z

On Fri, Feb 04, 2022 at 06:57:00AM -0500, Paolo Bonzini wrote:
> The init_kvm_*mmu functions, with the exception of shadow NPT,
> do not need to know the full values of CR0/CR4/EFER; they only
> need to know the bits that make up the "role". This cleanup
> however will take quite a few incremental steps. As a start,
> pull the common computation of the struct kvm_mmu_role_regs
> into their caller: all of them extract the struct from the vcpu
> as the very first step.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> arch/x86/kvm/mmu/mmu.c | 33 +++++++++++++++++----------------
> 1 file changed, 17 insertions(+), 16 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 3add9d8b0630..577e70509510 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -4736,12 +4736,12 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
> return role;
> }
>
> -static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
> +static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu,
> + const struct kvm_mmu_role_regs *regs)
> {
> struct kvm_mmu *context = &vcpu->arch.root_mmu;
> - struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
> union kvm_mmu_role new_role =
> - kvm_calc_tdp_mmu_root_page_role(vcpu, &regs, false);
> + kvm_calc_tdp_mmu_root_page_role(vcpu, regs, false);
>
> if (new_role.as_u64 == context->mmu_role.as_u64)
> return;
> @@ -4755,7 +4755,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
> context->get_guest_pgd = get_cr3;
> context->get_pdptr = kvm_pdptr_read;
> context->inject_page_fault = kvm_inject_page_fault;
> - context->root_level = role_regs_to_root_level(&regs);
> + context->root_level = role_regs_to_root_level(regs);
>
> if (!is_cr0_pg(context))
> context->gva_to_gpa = nonpaging_gva_to_gpa;
> @@ -4803,7 +4803,7 @@ kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu,
> }
>
> static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
> - struct kvm_mmu_role_regs *regs,
> + const struct kvm_mmu_role_regs *regs,
> union kvm_mmu_role new_role)
> {
> if (new_role.as_u64 == context->mmu_role.as_u64)
> @@ -4824,7 +4824,7 @@ static void shadow_mmu_init_context(struct kvm_vcpu *vcpu, struct kvm_mmu *conte
> }
>
> static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu,
> - struct kvm_mmu_role_regs *regs)
> + const struct kvm_mmu_role_regs *regs)
> {
> struct kvm_mmu *context = &vcpu->arch.root_mmu;
> union kvm_mmu_role new_role =
> @@ -4845,7 +4845,7 @@ static void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu,
>
> static union kvm_mmu_role
> kvm_calc_shadow_npt_root_page_role(struct kvm_vcpu *vcpu,
> - struct kvm_mmu_role_regs *regs)
> + const struct kvm_mmu_role_regs *regs)

Should these go in the previous commit? Aside from that,

Reviewed-by: David Matlack <dmatlack@google>

> {
> union kvm_mmu_role role =
> kvm_calc_shadow_root_page_role_common(vcpu, regs, false);
> @@ -4930,12 +4930,12 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
> }
> EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);
>
> -static void init_kvm_softmmu(struct kvm_vcpu *vcpu)
> +static void init_kvm_softmmu(struct kvm_vcpu *vcpu,
> + const struct kvm_mmu_role_regs *regs)
> {
> struct kvm_mmu *context = &vcpu->arch.root_mmu;
> - struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
>
> - kvm_init_shadow_mmu(vcpu, &regs);
> + kvm_init_shadow_mmu(vcpu, regs);
>
> context->get_guest_pgd = get_cr3;
> context->get_pdptr = kvm_pdptr_read;
> @@ -4959,10 +4959,9 @@ kvm_calc_nested_mmu_role(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *
> return role;
> }
>
> -static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
> +static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu, const struct kvm_mmu_role_regs *regs)
> {
> - struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
> - union kvm_mmu_role new_role = kvm_calc_nested_mmu_role(vcpu, &regs);
> + union kvm_mmu_role new_role = kvm_calc_nested_mmu_role(vcpu, regs);
> struct kvm_mmu *g_context = &vcpu->arch.nested_mmu;
>
> if (new_role.as_u64 == g_context->mmu_role.as_u64)
> @@ -5002,12 +5001,14 @@ static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
>
> void kvm_init_mmu(struct kvm_vcpu *vcpu)
> {
> + struct kvm_mmu_role_regs regs = vcpu_to_role_regs(vcpu);
> +
> if (mmu_is_nested(vcpu))
> - init_kvm_nested_mmu(vcpu);
> + init_kvm_nested_mmu(vcpu, &regs);
> else if (tdp_enabled)
> - init_kvm_tdp_mmu(vcpu);
> + init_kvm_tdp_mmu(vcpu, &regs);
> else
> - init_kvm_softmmu(vcpu);
> + init_kvm_softmmu(vcpu, &regs);
> }
> EXPORT_SYMBOL_GPL(kvm_init_mmu);
>
> --
> 2.31.1
>
>