From 7dcd575520082f186231777f4ac9f59ce14d6961 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Mon, 8 Oct 2018 21:28:12 +0200 Subject: [PATCH] x86/kvm/mmu: check if tdp/shadow MMU reconfiguration is needed MMU reconfiguration in init_kvm_tdp_mmu()/kvm_init_shadow_mmu() can be avoided if the source data used to configure it didn't change; enhance MMU extended role with the required fields and consolidate common code in kvm_calc_mmu_role_common(). Signed-off-by: Vitaly Kuznetsov Reviewed-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 2 + arch/x86/kvm/mmu.c | 95 +++++++++++++++++++++------------ 2 files changed, 63 insertions(+), 34 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index bf541af7442d..4b09d4aa9bf4 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -293,10 +293,12 @@ union kvm_mmu_extended_role { struct { unsigned int valid:1; unsigned int execonly:1; + unsigned int cr0_pg:1; unsigned int cr4_pse:1; unsigned int cr4_pke:1; unsigned int cr4_smap:1; unsigned int cr4_smep:1; + unsigned int cr4_la57:1; }; }; diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 9d400a06c5f2..9ed046fbab5e 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4728,27 +4728,46 @@ static union kvm_mmu_extended_role kvm_calc_mmu_role_ext(struct kvm_vcpu *vcpu) { union kvm_mmu_extended_role ext = {0}; + ext.cr0_pg = !!is_paging(vcpu); ext.cr4_smep = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMEP); ext.cr4_smap = !!kvm_read_cr4_bits(vcpu, X86_CR4_SMAP); ext.cr4_pse = !!is_pse(vcpu); ext.cr4_pke = !!kvm_read_cr4_bits(vcpu, X86_CR4_PKE); + ext.cr4_la57 = !!kvm_read_cr4_bits(vcpu, X86_CR4_LA57); ext.valid = 1; return ext; } -static union kvm_mmu_page_role -kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu) +static union kvm_mmu_role kvm_calc_mmu_role_common(struct kvm_vcpu *vcpu, + bool base_only) +{ + union kvm_mmu_role role = {0}; + + role.base.access = ACC_ALL; + role.base.nxe = !!is_nx(vcpu); + role.base.cr4_pae = !!is_pae(vcpu); + role.base.cr0_wp = is_write_protection(vcpu); + role.base.smm = is_smm(vcpu); + role.base.guest_mode = is_guest_mode(vcpu); + + if (base_only) + return role; + + role.ext = kvm_calc_mmu_role_ext(vcpu); + + return role; +} + +static union kvm_mmu_role +kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu, bool base_only) { - union kvm_mmu_page_role role = {0}; + union kvm_mmu_role role = kvm_calc_mmu_role_common(vcpu, base_only); - role.guest_mode = is_guest_mode(vcpu); - role.smm = is_smm(vcpu); - role.ad_disabled = (shadow_accessed_mask == 0); - role.level = kvm_x86_ops->get_tdp_level(vcpu); - role.direct = true; - role.access = ACC_ALL; + role.base.ad_disabled = (shadow_accessed_mask == 0); + role.base.level = kvm_x86_ops->get_tdp_level(vcpu); + role.base.direct = true; return role; } @@ -4756,9 +4775,14 @@ kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu) static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu) { struct kvm_mmu *context = vcpu->arch.mmu; + union kvm_mmu_role new_role = + kvm_calc_tdp_mmu_root_page_role(vcpu, false); - context->mmu_role.base.word = mmu_base_role_mask.word & - kvm_calc_tdp_mmu_root_page_role(vcpu).word; + new_role.base.word &= mmu_base_role_mask.word; + if (new_role.as_u64 == context->mmu_role.as_u64) + return; + + context->mmu_role.as_u64 = new_role.as_u64; context->page_fault = tdp_page_fault; context->sync_page = nonpaging_sync_page; context->invlpg = nonpaging_invlpg; @@ -4798,29 +4822,23 @@ static void init_kvm_tdp_mmu(struct kvm_vcpu *vcpu) reset_tdp_shadow_zero_bits_mask(vcpu, context); } -static union kvm_mmu_page_role -kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu) -{ - union kvm_mmu_page_role role = {0}; - bool smep = kvm_read_cr4_bits(vcpu, X86_CR4_SMEP); - bool smap = kvm_read_cr4_bits(vcpu, X86_CR4_SMAP); - - role.nxe = is_nx(vcpu); - role.cr4_pae = !!is_pae(vcpu); - role.cr0_wp = is_write_protection(vcpu); - role.smep_andnot_wp = smep && !is_write_protection(vcpu); - role.smap_andnot_wp = smap && !is_write_protection(vcpu); - role.guest_mode = is_guest_mode(vcpu); - role.smm = is_smm(vcpu); - role.direct = !is_paging(vcpu); - role.access = ACC_ALL; +static union kvm_mmu_role +kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu, bool base_only) +{ + union kvm_mmu_role role = kvm_calc_mmu_role_common(vcpu, base_only); + + role.base.smep_andnot_wp = role.ext.cr4_smep && + !is_write_protection(vcpu); + role.base.smap_andnot_wp = role.ext.cr4_smap && + !is_write_protection(vcpu); + role.base.direct = !is_paging(vcpu); if (!is_long_mode(vcpu)) - role.level = PT32E_ROOT_LEVEL; + role.base.level = PT32E_ROOT_LEVEL; else if (is_la57_mode(vcpu)) - role.level = PT64_ROOT_5LEVEL; + role.base.level = PT64_ROOT_5LEVEL; else - role.level = PT64_ROOT_4LEVEL; + role.base.level = PT64_ROOT_4LEVEL; return role; } @@ -4828,6 +4846,12 @@ kvm_calc_shadow_mmu_root_page_role(struct kvm_vcpu *vcpu) void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu) { struct kvm_mmu *context = vcpu->arch.mmu; + union kvm_mmu_role new_role = + kvm_calc_shadow_mmu_root_page_role(vcpu, false); + + new_role.base.word &= mmu_base_role_mask.word; + if (new_role.as_u64 == context->mmu_role.as_u64) + return; if (!is_paging(vcpu)) nonpaging_init_context(vcpu, context); @@ -4838,8 +4862,7 @@ void kvm_init_shadow_mmu(struct kvm_vcpu *vcpu) else paging32_init_context(vcpu, context); - context->mmu_role.base.word = mmu_base_role_mask.word & - kvm_calc_shadow_mmu_root_page_role(vcpu).word; + context->mmu_role.as_u64 = new_role.as_u64; reset_shadow_zero_bits_mask(vcpu, context); } EXPORT_SYMBOL_GPL(kvm_init_shadow_mmu); @@ -4977,10 +5000,14 @@ EXPORT_SYMBOL_GPL(kvm_init_mmu); static union kvm_mmu_page_role kvm_mmu_calc_root_page_role(struct kvm_vcpu *vcpu) { + union kvm_mmu_role role; + if (tdp_enabled) - return kvm_calc_tdp_mmu_root_page_role(vcpu); + role = kvm_calc_tdp_mmu_root_page_role(vcpu, true); else - return kvm_calc_shadow_mmu_root_page_role(vcpu); + role = kvm_calc_shadow_mmu_root_page_role(vcpu, true); + + return role.base; } void kvm_mmu_reset_context(struct kvm_vcpu *vcpu) -- 2.30.2