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Message-ID: <524D5A2D.6070001@redhat.com>
Date: Thu, 03 Oct 2013 13:51:09 +0200
From: Paolo Bonzini <pbonzini@...hat.com>
To: Gleb Natapov <gleb@...hat.com>
CC: linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH 5/7] KVM: mmu: remove argument to kvm_init_shadow_mmu
and kvm_init_shadow_ept_mmu
Il 03/10/2013 13:25, Gleb Natapov ha scritto:
> On Wed, Oct 02, 2013 at 04:56:14PM +0200, Paolo Bonzini wrote:
>> The initialization function in mmu.c can always use walk_mmu, which
>> is known to be vcpu->arch.mmu. Only init_kvm_nested_mmu is used to
>> initialize vcpu->arch.nested_mmu.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
>> ---
>> arch/x86/kvm/mmu.c | 15 +++++++++------
>> arch/x86/kvm/mmu.h | 5 ++---
>> arch/x86/kvm/svm.c | 4 ++--
>> arch/x86/kvm/vmx.c | 4 ++--
>> 4 files changed, 15 insertions(+), 13 deletions(-)
>>
>> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
>> index 40772ef..ac598c8 100644
>> --- a/arch/x86/kvm/mmu.c
>> +++ b/arch/x86/kvm/mmu.c
>> @@ -3742,11 +3742,13 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
>> update_last_pte_bitmap(vcpu, context);
>> }
>>
>> -void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
>> +void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu)
>> {
>> bool smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
>> + struct kvm_mmu *context = vcpu->arch.walk_mmu;
> I'd rather use &vcpu->arch.mmu here.
>
>> +
>> ASSERT(vcpu);
>> - ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
>> + ASSERT(!VALID_PAGE(context->root_hpa));
>>
>> if (!is_paging(vcpu))
>> nonpaging_init_context(vcpu, context);
>> @@ -3765,11 +3767,12 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
>> }
>> EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
>>
>> -void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
>> - bool execonly)
>> +void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly)
>> {
>> + struct kvm_mmu *context = vcpu->arch.walk_mmu;
>> +
>> ASSERT(vcpu);
>> - ASSERT(!VALID_PAGE(vcpu->arch.mmu.root_hpa));
>> + ASSERT(!VALID_PAGE(context->root_hpa));
>>
>> context->shadow_root_level = kvm_x86_ops->get_tdp_level();
>>
>> @@ -3790,7 +3793,7 @@ EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);
>>
>> static void init_kvm_softmmu(struct kvm_vcpu *vcpu)
>> {
>> - kvm_init_shadow_mmu(vcpu, vcpu->arch.walk_mmu);
>> + kvm_init_shadow_mmu(vcpu);
>> vcpu->arch.walk_mmu->set_cr3 = kvm_x86_ops->set_cr3;
>> vcpu->arch.walk_mmu->get_cr3 = get_cr3;
>> vcpu->arch.walk_mmu->get_pdptr = kvm_pdptr_read;
> And change walk_mmu to mmu here too for consistency with all other
> places. Basically if you want to initialize use mmu or nested_mmu.
> Use walk_mmu pointer only when you need to use mmu.
Makes sense, especially considering how kvm_init_shadow_mmu initializes
vcpu->arch.mmu.base_role directly.
Something like this (large enough that I'll probably make it a separate
patch in v2)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index ac598c8..d1f53cf 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3702,7 +3704,7 @@ static void paging32E_init_context(struct kvm_vcpu *vcpu,
static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
{
- struct kvm_mmu *context = vcpu->arch.walk_mmu;
+ struct kvm_mmu *context = &vcpu->arch.mmu;
context->base_role.word = 0;
context->page_fault = tdp_page_fault;
@@ -3745,7 +3747,7 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu)
void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu)
{
bool smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP);
- struct kvm_mmu *context = vcpu->arch.walk_mmu;
+ struct kvm_mmu *context = &vcpu->arch.mmu;
ASSERT(vcpu);
ASSERT(!VALID_PAGE(context->root_hpa));
@@ -3759,17 +3761,17 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu)
else
paging32_init_context(vcpu, context);
- vcpu->arch.mmu.base_role.nxe = is_nx(vcpu);
- vcpu->arch.mmu.base_role.cr4_pae = !!is_pae(vcpu);
- vcpu->arch.mmu.base_role.cr0_wp = is_write_protection(vcpu);
- vcpu->arch.mmu.base_role.smep_andnot_wp
+ context->base_role.nxe = is_nx(vcpu);
+ context->base_role.cr4_pae = !!is_pae(vcpu);
+ context->base_role.cr0_wp = is_write_protection(vcpu);
+ context->base_role.smep_andnot_wp
= smep && !is_write_protection(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu);
void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly)
{
- struct kvm_mmu *context = vcpu->arch.walk_mmu;
+ struct kvm_mmu *context = &vcpu->arch.mmu;
ASSERT(vcpu);
ASSERT(!VALID_PAGE(context->root_hpa));
@@ -3793,11 +3795,13 @@ EXPORT_SYMBOL_GPL(kvm_init_shadow_ept_mmu);
static void init_kvm_softmmu(struct kvm_vcpu *vcpu)
{
+ struct kvm_mmu *context = &vcpu->arch.mmu;
+
kvm_init_shadow_mmu(vcpu);
- vcpu->arch.walk_mmu->set_cr3 = kvm_x86_ops->set_cr3;
- vcpu->arch.walk_mmu->get_cr3 = get_cr3;
- vcpu->arch.walk_mmu->get_pdptr = kvm_pdptr_read;
- vcpu->arch.walk_mmu->inject_page_fault = kvm_inject_page_fault;
+ context->set_cr3 = kvm_x86_ops->set_cr3;
+ context->get_cr3 = get_cr3;
+ context->get_pdptr = kvm_pdptr_read;
+ context->inject_page_fault = kvm_inject_page_fault;
}
static void init_kvm_nested_mmu(struct kvm_vcpu *vcpu)
How far should I go? Should I also remove the context argument from
nonpaging_init_context and friends, changing it to a local variable?
(Doesn't seem like a big improvement in clarity).
Paolo
>> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
>> index 2926152..c9d3d8f 100644
>> --- a/arch/x86/kvm/mmu.h
>> +++ b/arch/x86/kvm/mmu.h
>> @@ -70,9 +70,8 @@ enum {
>> };
>>
>> int handle_mmio_page_fault_common(struct kvm_vcpu *vcpu, u64 addr, bool direct);
>> -void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context);
>> -void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *context,
>> - bool execonly);
>> +void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu);
>> +void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly);
>>
>> static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm)
>> {
>> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
>> index c7168a5..37bcd6b 100644
>> --- a/arch/x86/kvm/svm.c
>> +++ b/arch/x86/kvm/svm.c
>> @@ -1961,8 +1961,8 @@ static void nested_svm_inject_npf_exit(struct kvm_vcpu *vcpu,
>>
>> static void nested_svm_init_mmu_context(struct kvm_vcpu *vcpu)
>> {
>> - kvm_init_shadow_mmu(vcpu, &vcpu->arch.mmu);
>> -
>> + WARN_ON(mmu_is_nested(vcpu));
>> + kvm_init_shadow_mmu(vcpu);
>> vcpu->arch.mmu.set_cr3 = nested_svm_set_tdp_cr3;
>> vcpu->arch.mmu.get_cr3 = nested_svm_get_tdp_cr3;
>> vcpu->arch.mmu.get_pdptr = nested_svm_get_tdp_pdptr;
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 2db9164..fdd1cb8 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -7501,9 +7501,9 @@ static unsigned long nested_ept_get_cr3(struct kvm_vcpu *vcpu)
>>
>> static void nested_ept_init_mmu_context(struct kvm_vcpu *vcpu)
>> {
>> - kvm_init_shadow_ept_mmu(vcpu, &vcpu->arch.mmu,
>> + WARN_ON(mmu_is_nested(vcpu));
>> + kvm_init_shadow_ept_mmu(vcpu,
>> nested_vmx_ept_caps & VMX_EPT_EXECUTE_ONLY_BIT);
>> -
>> vcpu->arch.mmu.set_cr3 = vmx_set_cr3;
>> vcpu->arch.mmu.get_cr3 = nested_ept_get_cr3;
>> vcpu->arch.mmu.inject_page_fault = nested_ept_inject_page_fault;
>> --
>> 1.8.3.1
>>
>
> --
> Gleb.
>
--
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