| Message ID | 20200305183725.28872-3-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: VMX: cleanup VMXON region allocation | expand |
On Thu, Mar 05, 2020 at 07:37:25PM +0100, Vitaly Kuznetsov wrote: > As stated in alloc_vmxon_regions(), VMXON region needs to be tagged with > revision id from MSR_IA32_VMX_BASIC even in case of eVMCS. The logic to > do so is not very straightforward: first, we set > hdr.revision_id = KVM_EVMCS_VERSION in alloc_vmcs_cpu() just to reset it > back to vmcs_config.revision_id in alloc_vmxon_regions(). Simplify this by > introducing 'enum vmcs_type' parameter to alloc_vmcs_cpu(). > > No functional change intended. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> > --- ... > + * However, even though not explicitly documented by TLFS, VMXArea > + * passed as VMXON argument should still be marked with revision_id > + * reported by physical CPU. LOL, nice. > + */ > + if (type != VMXON_REGION && static_branch_unlikely(&enable_evmcs)) > vmcs->hdr.revision_id = KVM_EVMCS_VERSION; > else > vmcs->hdr.revision_id = vmcs_config.revision_id; > > - if (shadow) > + if (type == SHADOW_VMCS_REGION) > vmcs->hdr.shadow_vmcs = 1; > return vmcs; > } > -struct vmcs *alloc_vmcs_cpu(bool shadow, int cpu, gfp_t flags); > +enum vmcs_type { > + VMXON_REGION, > + VMCS_REGION, > + SHADOW_VMCS_REGION, > +}; > + > +struct vmcs *alloc_vmcs_cpu(enum vmcs_type type, int cpu, gfp_t flags); > void free_vmcs(struct vmcs *vmcs); > int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs); > void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs); > @@ -498,8 +504,8 @@ void loaded_vmcs_clear(struct loaded_vmcs *loaded_vmcs); > > static inline struct vmcs *alloc_vmcs(bool shadow) I think it'd be cleaner overall to take "enum vmcs_type" in alloc_vmcs(). Then the ternary operator goes away and the callers (all two of 'em) are self-documenting. E.g. diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 79c7764c77b1..2c8a0a1386b1 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -4566,7 +4566,7 @@ static struct vmcs *alloc_shadow_vmcs(struct kvm_vcpu *vcpu) WARN_ON(loaded_vmcs == &vmx->vmcs01 && loaded_vmcs->shadow_vmcs); if (!loaded_vmcs->shadow_vmcs) { - loaded_vmcs->shadow_vmcs = alloc_vmcs(true); + loaded_vmcs->shadow_vmcs = alloc_vmcs(SHADOW_VMCS_REGION); if (loaded_vmcs->shadow_vmcs) vmcs_clear(loaded_vmcs->shadow_vmcs); } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 5bdf6919de83..4634f6d7d55a 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2605,7 +2605,7 @@ void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs) int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs) { - loaded_vmcs->vmcs = alloc_vmcs(false); + loaded_vmcs->vmcs = alloc_vmcs(VMCS_REGION); if (!loaded_vmcs->vmcs) return -ENOMEM; diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 4c327030bb9c..a5eb92638ac2 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -502,10 +502,10 @@ void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs); void loaded_vmcs_init(struct loaded_vmcs *loaded_vmcs); void loaded_vmcs_clear(struct loaded_vmcs *loaded_vmcs); -static inline struct vmcs *alloc_vmcs(bool shadow) +static inline struct vmcs *alloc_vmcs(enum vmcs_type type) { - return alloc_vmcs_cpu(shadow ? SHADOW_VMCS_REGION : VMCS_REGION, - raw_smp_processor_id(), GFP_KERNEL_ACCOUNT); + return alloc_vmcs_cpu(type, raw_smp_processor_id(), + GFP_KERNEL_ACCOUNT); } u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa); > { > - return alloc_vmcs_cpu(shadow, raw_smp_processor_id(), > - GFP_KERNEL_ACCOUNT); > + return alloc_vmcs_cpu(shadow ? SHADOW_VMCS_REGION : VMCS_REGION, > + raw_smp_processor_id(), GFP_KERNEL_ACCOUNT); > } > > u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa); > -- > 2.24.1 >
Sean Christopherson <sean.j.christopherson@intel.com> writes: > On Thu, Mar 05, 2020 at 07:37:25PM +0100, Vitaly Kuznetsov wrote: >> As stated in alloc_vmxon_regions(), VMXON region needs to be tagged with >> revision id from MSR_IA32_VMX_BASIC even in case of eVMCS. The logic to >> do so is not very straightforward: first, we set >> hdr.revision_id = KVM_EVMCS_VERSION in alloc_vmcs_cpu() just to reset it >> back to vmcs_config.revision_id in alloc_vmxon_regions(). Simplify this by >> introducing 'enum vmcs_type' parameter to alloc_vmcs_cpu(). >> >> No functional change intended. >> >> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> >> --- > > ... > >> + * However, even though not explicitly documented by TLFS, VMXArea >> + * passed as VMXON argument should still be marked with revision_id >> + * reported by physical CPU. > > LOL, nice. > > >> + */ >> + if (type != VMXON_REGION && static_branch_unlikely(&enable_evmcs)) >> vmcs->hdr.revision_id = KVM_EVMCS_VERSION; >> else >> vmcs->hdr.revision_id = vmcs_config.revision_id; >> >> - if (shadow) >> + if (type == SHADOW_VMCS_REGION) >> vmcs->hdr.shadow_vmcs = 1; >> return vmcs; >> } > >> -struct vmcs *alloc_vmcs_cpu(bool shadow, int cpu, gfp_t flags); >> +enum vmcs_type { >> + VMXON_REGION, >> + VMCS_REGION, >> + SHADOW_VMCS_REGION, >> +}; >> + >> +struct vmcs *alloc_vmcs_cpu(enum vmcs_type type, int cpu, gfp_t flags); >> void free_vmcs(struct vmcs *vmcs); >> int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs); >> void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs); >> @@ -498,8 +504,8 @@ void loaded_vmcs_clear(struct loaded_vmcs *loaded_vmcs); >> >> static inline struct vmcs *alloc_vmcs(bool shadow) > > I think it'd be cleaner overall to take "enum vmcs_type" in alloc_vmcs(). > Then the ternary operator goes away and the callers (all two of 'em) are > self-documenting. Ya, it didn't seem to be needed with my initial suggestion to rename alloc_vmcs_cpu() to alloc_vmx_area_cpu() because in case we think of VMXON region as something different from VMCS we have only two options: normal VMCS or shadow VMCS and bool flag works perfectly. v3 is on the way, stay tuned!
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index dab19e4e5f2b..697be8823576 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -2554,7 +2554,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf, return 0; } -struct vmcs *alloc_vmcs_cpu(bool shadow, int cpu, gfp_t flags) +struct vmcs *alloc_vmcs_cpu(enum vmcs_type type, int cpu, gfp_t flags) { int node = cpu_to_node(cpu); struct page *pages; @@ -2566,13 +2566,21 @@ struct vmcs *alloc_vmcs_cpu(bool shadow, int cpu, gfp_t flags) vmcs = page_address(pages); memset(vmcs, 0, vmcs_config.size); - /* KVM supports Enlightened VMCS v1 only */ - if (static_branch_unlikely(&enable_evmcs)) + /* + * When eVMCS is enabled, vmcs->revision_id needs to be set to the + * supported eVMCS version (KVM_EVMCS_VERSION) instead of revision_id + * reported by MSR_IA32_VMX_BASIC. + * + * However, even though not explicitly documented by TLFS, VMXArea + * passed as VMXON argument should still be marked with revision_id + * reported by physical CPU. + */ + if (type != VMXON_REGION && static_branch_unlikely(&enable_evmcs)) vmcs->hdr.revision_id = KVM_EVMCS_VERSION; else vmcs->hdr.revision_id = vmcs_config.revision_id; - if (shadow) + if (type == SHADOW_VMCS_REGION) vmcs->hdr.shadow_vmcs = 1; return vmcs; } @@ -2652,25 +2660,13 @@ static __init int alloc_vmxon_regions(void) for_each_possible_cpu(cpu) { struct vmcs *vmcs; - vmcs = alloc_vmcs_cpu(false, cpu, GFP_KERNEL); + /* The VMXON region is really just a special type of VMCS. */ + vmcs = alloc_vmcs_cpu(VMXON_REGION, cpu, GFP_KERNEL); if (!vmcs) { free_vmxon_regions(); return -ENOMEM; } - /* - * When eVMCS is enabled, alloc_vmcs_cpu() sets - * vmcs->revision_id to KVM_EVMCS_VERSION instead of - * revision_id reported by MSR_IA32_VMX_BASIC. - * - * However, even though not explicitly documented by - * TLFS, VMXArea passed as VMXON argument should - * still be marked with revision_id reported by - * physical CPU. - */ - if (static_branch_unlikely(&enable_evmcs)) - vmcs->hdr.revision_id = vmcs_config.revision_id; - per_cpu(vmxarea, cpu) = vmcs; } return 0; diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index e64da06c7009..4c327030bb9c 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -489,7 +489,13 @@ static inline struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu *vcpu) return &(to_vmx(vcpu)->pi_desc); } -struct vmcs *alloc_vmcs_cpu(bool shadow, int cpu, gfp_t flags); +enum vmcs_type { + VMXON_REGION, + VMCS_REGION, + SHADOW_VMCS_REGION, +}; + +struct vmcs *alloc_vmcs_cpu(enum vmcs_type type, int cpu, gfp_t flags); void free_vmcs(struct vmcs *vmcs); int alloc_loaded_vmcs(struct loaded_vmcs *loaded_vmcs); void free_loaded_vmcs(struct loaded_vmcs *loaded_vmcs); @@ -498,8 +504,8 @@ void loaded_vmcs_clear(struct loaded_vmcs *loaded_vmcs); static inline struct vmcs *alloc_vmcs(bool shadow) { - return alloc_vmcs_cpu(shadow, raw_smp_processor_id(), - GFP_KERNEL_ACCOUNT); + return alloc_vmcs_cpu(shadow ? SHADOW_VMCS_REGION : VMCS_REGION, + raw_smp_processor_id(), GFP_KERNEL_ACCOUNT); } u64 construct_eptp(struct kvm_vcpu *vcpu, unsigned long root_hpa);
As stated in alloc_vmxon_regions(), VMXON region needs to be tagged with revision id from MSR_IA32_VMX_BASIC even in case of eVMCS. The logic to do so is not very straightforward: first, we set hdr.revision_id = KVM_EVMCS_VERSION in alloc_vmcs_cpu() just to reset it back to vmcs_config.revision_id in alloc_vmxon_regions(). Simplify this by introducing 'enum vmcs_type' parameter to alloc_vmcs_cpu(). No functional change intended. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- arch/x86/kvm/vmx/vmx.c | 32 ++++++++++++++------------------ arch/x86/kvm/vmx/vmx.h | 12 +++++++++--- 2 files changed, 23 insertions(+), 21 deletions(-)