| Message ID | 1483943091-1364-40-git-send-email-jintack@cs.columbia.edu (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jan 09, 2017 at 01:24:35AM -0500, Jintack Lim wrote: > Add the shadow stage-2 MMU context to be used for the nesting, but don't > do anything with it yet. > > The host hypervisor maintains mmu structures for each nested VM. When > entering a nested VM, the host hypervisor searches for the nested VM's > mmu using vmid as a key. Note that this vmid is from the guest > hypervisor's point of view. I feel like I'm missing some overall design description or rationale of why this is needed. Can you expand on this commit message a bit? > > Signed-off-by: Jintack Lim <jintack@cs.columbia.edu> > --- > arch/arm/include/asm/kvm_host.h | 3 ++ > arch/arm/kvm/arm.c | 1 + > arch/arm64/include/asm/kvm_emulate.h | 13 ++++----- > arch/arm64/include/asm/kvm_host.h | 19 +++++++++++++ > arch/arm64/include/asm/kvm_mmu.h | 31 ++++++++++++++++++++ > arch/arm64/kvm/Makefile | 1 + > arch/arm64/kvm/context.c | 2 +- > arch/arm64/kvm/mmu-nested.c | 55 ++++++++++++++++++++++++++++++++++++ > 8 files changed, 116 insertions(+), 9 deletions(-) > create mode 100644 arch/arm64/kvm/mmu-nested.c > > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h > index da45394..fbde48d 100644 > --- a/arch/arm/include/asm/kvm_host.h > +++ b/arch/arm/include/asm/kvm_host.h > @@ -82,6 +82,9 @@ struct kvm_arch { > * here. > */ > > + /* Never used on arm but added to be compatible with arm64 */ > + struct list_head nested_mmu_list; > + > /* Interrupt controller */ > struct vgic_dist vgic; > int max_vcpus; > diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c > index 371b38e7..147df97 100644 > --- a/arch/arm/kvm/arm.c > +++ b/arch/arm/kvm/arm.c > @@ -146,6 +146,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) > /* Mark the initial VMID generation invalid */ > kvm->arch.mmu.vmid.vmid_gen = 0; > kvm->arch.mmu.el2_vmid.vmid_gen = 0; > + INIT_LIST_HEAD(&kvm->arch.nested_mmu_list); > > /* The maximum number of VCPUs is limited by the host's GIC model */ > kvm->arch.max_vcpus = vgic_present ? > diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h > index 94068e7..abad676 100644 > --- a/arch/arm64/include/asm/kvm_emulate.h > +++ b/arch/arm64/include/asm/kvm_emulate.h > @@ -183,6 +183,11 @@ static inline bool vcpu_el2_imo_is_set(const struct kvm_vcpu *vcpu) > return (vcpu_el2_reg(vcpu, HCR_EL2) & HCR_IMO); > } > > +static inline bool vcpu_nested_stage2_enabled(const struct kvm_vcpu *vcpu) > +{ > + return (vcpu_el2_reg(vcpu, HCR_EL2) & HCR_VM); > +} > + > static inline u32 kvm_vcpu_get_hsr(const struct kvm_vcpu *vcpu) > { > return vcpu->arch.fault.esr_el2; > @@ -363,12 +368,4 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, > return data; /* Leave LE untouched */ > } > > -static inline struct kvm_s2_vmid *vcpu_get_active_vmid(struct kvm_vcpu *vcpu) > -{ > - if (unlikely(vcpu_mode_el2(vcpu))) > - return &vcpu->kvm->arch.mmu.el2_vmid; > - > - return &vcpu->kvm->arch.mmu.vmid; > -} > - > #endif /* __ARM64_KVM_EMULATE_H__ */ > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index b33d35d..23e2267 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -65,6 +65,22 @@ struct kvm_s2_mmu { > pgd_t *pgd; > }; > > +/* Per nested VM mmu structure */ > +struct kvm_nested_s2_mmu { > + struct kvm_s2_mmu mmu; > + > + /* > + * The vttbr value set by the guest hypervisor for this nested VM. > + * vmid field is used as a key to search for this mmu structure among > + * all nested VM mmu structures by the host hypervisor. > + * baddr field is used to determine if we need to unmap stage 2 > + * shadow page tables. > + */ I don't really understand this comment in isolation - especially not the baddr part. > + u64 virtual_vttbr; > + > + struct list_head list; > +}; > + > struct kvm_arch { > /* Stage 2 paging state for the VM */ > struct kvm_s2_mmu mmu; > @@ -80,6 +96,9 @@ struct kvm_arch { > > /* Timer */ > struct arch_timer_kvm timer; > + > + /* Stage 2 shadow paging contexts for nested L2 VM */ > + struct list_head nested_mmu_list; > }; > > #define KVM_NR_MEM_OBJS 40 > diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h > index a504162..d1ef650 100644 > --- a/arch/arm64/include/asm/kvm_mmu.h > +++ b/arch/arm64/include/asm/kvm_mmu.h > @@ -112,6 +112,7 @@ > #include <asm/cacheflush.h> > #include <asm/mmu_context.h> > #include <asm/pgtable.h> > +#include <asm/kvm_emulate.h> > > static inline unsigned long __kern_hyp_va(unsigned long v) > { > @@ -323,6 +324,21 @@ static inline unsigned int kvm_get_vmid_bits(void) > return (cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR1_VMIDBITS_SHIFT) == 2) ? 16 : 8; > } > > +#ifdef CONFIG_KVM_ARM_NESTED_HYP > +struct kvm_nested_s2_mmu *get_nested_mmu(struct kvm_vcpu *vcpu, u64 vttbr); > +struct kvm_s2_mmu *vcpu_get_active_s2_mmu(struct kvm_vcpu *vcpu); > +#else > +static inline struct kvm_nested_s2_mmu *get_nested_mmu(struct kvm_vcpu *vcpu, > + u64 vttbr) > +{ > + return NULL; > +} > +static inline struct kvm_s2_mmu *vcpu_get_active_s2_mmu(struct kvm_vcpu *vcpu) > +{ > + return &vcpu->kvm->arch.mmu; > +} > +#endif > + > static inline u64 kvm_get_vttbr(struct kvm_s2_vmid *vmid, > struct kvm_s2_mmu *mmu) > { > @@ -334,5 +350,20 @@ static inline u64 kvm_get_vttbr(struct kvm_s2_vmid *vmid, > return baddr | vmid_field; > } > > +static inline u64 get_vmid(u64 vttbr) > +{ > + return (vttbr & VTTBR_VMID_MASK(get_kvm_vmid_bits()))>>VTTBR_VMID_SHIFT; whitespacealertbetweentheshiftmarker. > +} > + > +static inline struct kvm_s2_vmid *vcpu_get_active_vmid(struct kvm_vcpu *vcpu) > +{ > + struct kvm_s2_mmu *mmu = vcpu_get_active_s2_mmu(vcpu); > + > + if (unlikely(vcpu_mode_el2(vcpu))) > + return &mmu->el2_vmid; > + else > + return &mmu->vmid; > +} > + > #endif /* __ASSEMBLY__ */ > #endif /* __ARM64_KVM_MMU_H__ */ > diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile > index 8573faf..b0b1074 100644 > --- a/arch/arm64/kvm/Makefile > +++ b/arch/arm64/kvm/Makefile > @@ -36,5 +36,6 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arch_timer.o > kvm-$(CONFIG_KVM_ARM_PMU) += $(KVM)/arm/pmu.o > > kvm-$(CONFIG_KVM_ARM_NESTED_HYP) += handle_exit_nested.o > +kvm-$(CONFIG_KVM_ARM_NESTED_HYP) += mmu-nested.o > kvm-$(CONFIG_KVM_ARM_NESTED_HYP) += emulate-nested.o > kvm-$(CONFIG_KVM_ARM_NESTED_HYP) += $(KVM)/arm/vgic/vgic-v2-nested.o > diff --git a/arch/arm64/kvm/context.c b/arch/arm64/kvm/context.c > index b2c0220..9ebc38f 100644 > --- a/arch/arm64/kvm/context.c > +++ b/arch/arm64/kvm/context.c > @@ -91,7 +91,7 @@ static void create_shadow_el1_sysregs(struct kvm_vcpu *vcpu) > > static void setup_s2_mmu(struct kvm_vcpu *vcpu) > { > - struct kvm_s2_mmu *mmu = &vcpu->kvm->arch.mmu; > + struct kvm_s2_mmu *mmu = vcpu_get_active_s2_mmu(vcpu); > struct kvm_s2_vmid *vmid = vcpu_get_active_vmid(vcpu); > > vcpu->arch.hw_vttbr = kvm_get_vttbr(vmid, mmu); > diff --git a/arch/arm64/kvm/mmu-nested.c b/arch/arm64/kvm/mmu-nested.c > new file mode 100644 > index 0000000..d52078f > --- /dev/null > +++ b/arch/arm64/kvm/mmu-nested.c > @@ -0,0 +1,55 @@ > +/* > + * Copyright (C) 2016 - Columbia University > + * Author: Jintack Lim <jintack@cs.columbia.edu> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see <http://www.gnu.org/licenses/>. > + */ > + > +#include <linux/kvm_host.h> > + > +#include <asm/kvm_arm.h> > +#include <asm/kvm_emulate.h> > +#include <asm/kvm_mmu.h> > +#include <asm/kvm_nested.h> > + > +struct kvm_nested_s2_mmu *get_nested_mmu(struct kvm_vcpu *vcpu, u64 vttbr) > +{ > + struct kvm_nested_s2_mmu *mmu; > + u64 target_vmid = get_vmid(vttbr); > + struct list_head *nested_mmu_list = &vcpu->kvm->arch.nested_mmu_list; > + > + list_for_each_entry_rcu(mmu, nested_mmu_list, list) { > + u64 vmid = get_vmid(mmu->virtual_vttbr); > + > + if (target_vmid == vmid) why is it sufficient to just look at the VMID and not having to consider the baddr? > + return mmu; > + } > + return NULL; > +} > + > +struct kvm_s2_mmu *vcpu_get_active_s2_mmu(struct kvm_vcpu *vcpu) > +{ > + struct kvm_nested_s2_mmu *nested_mmu; > + > + /* If we are NOT entering the nested VM, return mmu in kvm_arch */ this comment doesn't add any info not clear in the code > + if (vcpu_mode_el2(vcpu) || !vcpu_nested_stage2_enabled(vcpu)) > + return &vcpu->kvm->arch.mmu; > + > + /* Otherwise, search for nested_mmu in the list */ > + nested_mmu = get_nested_mmu(vcpu, vcpu_el2_reg(vcpu, VTTBR_EL2)); > + > + /* When this function is called, nested_mmu should be in the list */ > + BUG_ON(!nested_mmu); can you provide a slightly stronger rationale behind why this BUG_ON should never fire - I don't feel convinced right now. > + > + return &nested_mmu->mmu; > +} > -- > 1.9.1 > > Thanks, -Christoffer
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index da45394..fbde48d 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -82,6 +82,9 @@ struct kvm_arch { * here. */ + /* Never used on arm but added to be compatible with arm64 */ + struct list_head nested_mmu_list; + /* Interrupt controller */ struct vgic_dist vgic; int max_vcpus; diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index 371b38e7..147df97 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -146,6 +146,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) /* Mark the initial VMID generation invalid */ kvm->arch.mmu.vmid.vmid_gen = 0; kvm->arch.mmu.el2_vmid.vmid_gen = 0; + INIT_LIST_HEAD(&kvm->arch.nested_mmu_list); /* The maximum number of VCPUs is limited by the host's GIC model */ kvm->arch.max_vcpus = vgic_present ? diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 94068e7..abad676 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -183,6 +183,11 @@ static inline bool vcpu_el2_imo_is_set(const struct kvm_vcpu *vcpu) return (vcpu_el2_reg(vcpu, HCR_EL2) & HCR_IMO); } +static inline bool vcpu_nested_stage2_enabled(const struct kvm_vcpu *vcpu) +{ + return (vcpu_el2_reg(vcpu, HCR_EL2) & HCR_VM); +} + static inline u32 kvm_vcpu_get_hsr(const struct kvm_vcpu *vcpu) { return vcpu->arch.fault.esr_el2; @@ -363,12 +368,4 @@ static inline unsigned long vcpu_data_host_to_guest(struct kvm_vcpu *vcpu, return data; /* Leave LE untouched */ } -static inline struct kvm_s2_vmid *vcpu_get_active_vmid(struct kvm_vcpu *vcpu) -{ - if (unlikely(vcpu_mode_el2(vcpu))) - return &vcpu->kvm->arch.mmu.el2_vmid; - - return &vcpu->kvm->arch.mmu.vmid; -} - #endif /* __ARM64_KVM_EMULATE_H__ */ diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index b33d35d..23e2267 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -65,6 +65,22 @@ struct kvm_s2_mmu { pgd_t *pgd; }; +/* Per nested VM mmu structure */ +struct kvm_nested_s2_mmu { + struct kvm_s2_mmu mmu; + + /* + * The vttbr value set by the guest hypervisor for this nested VM. + * vmid field is used as a key to search for this mmu structure among + * all nested VM mmu structures by the host hypervisor. + * baddr field is used to determine if we need to unmap stage 2 + * shadow page tables. + */ + u64 virtual_vttbr; + + struct list_head list; +}; + struct kvm_arch { /* Stage 2 paging state for the VM */ struct kvm_s2_mmu mmu; @@ -80,6 +96,9 @@ struct kvm_arch { /* Timer */ struct arch_timer_kvm timer; + + /* Stage 2 shadow paging contexts for nested L2 VM */ + struct list_head nested_mmu_list; }; #define KVM_NR_MEM_OBJS 40 diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index a504162..d1ef650 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -112,6 +112,7 @@ #include <asm/cacheflush.h> #include <asm/mmu_context.h> #include <asm/pgtable.h> +#include <asm/kvm_emulate.h> static inline unsigned long __kern_hyp_va(unsigned long v) { @@ -323,6 +324,21 @@ static inline unsigned int kvm_get_vmid_bits(void) return (cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR1_VMIDBITS_SHIFT) == 2) ? 16 : 8; } +#ifdef CONFIG_KVM_ARM_NESTED_HYP +struct kvm_nested_s2_mmu *get_nested_mmu(struct kvm_vcpu *vcpu, u64 vttbr); +struct kvm_s2_mmu *vcpu_get_active_s2_mmu(struct kvm_vcpu *vcpu); +#else +static inline struct kvm_nested_s2_mmu *get_nested_mmu(struct kvm_vcpu *vcpu, + u64 vttbr) +{ + return NULL; +} +static inline struct kvm_s2_mmu *vcpu_get_active_s2_mmu(struct kvm_vcpu *vcpu) +{ + return &vcpu->kvm->arch.mmu; +} +#endif + static inline u64 kvm_get_vttbr(struct kvm_s2_vmid *vmid, struct kvm_s2_mmu *mmu) { @@ -334,5 +350,20 @@ static inline u64 kvm_get_vttbr(struct kvm_s2_vmid *vmid, return baddr | vmid_field; } +static inline u64 get_vmid(u64 vttbr) +{ + return (vttbr & VTTBR_VMID_MASK(get_kvm_vmid_bits()))>>VTTBR_VMID_SHIFT; +} + +static inline struct kvm_s2_vmid *vcpu_get_active_vmid(struct kvm_vcpu *vcpu) +{ + struct kvm_s2_mmu *mmu = vcpu_get_active_s2_mmu(vcpu); + + if (unlikely(vcpu_mode_el2(vcpu))) + return &mmu->el2_vmid; + else + return &mmu->vmid; +} + #endif /* __ASSEMBLY__ */ #endif /* __ARM64_KVM_MMU_H__ */ diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile index 8573faf..b0b1074 100644 --- a/arch/arm64/kvm/Makefile +++ b/arch/arm64/kvm/Makefile @@ -36,5 +36,6 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arch_timer.o kvm-$(CONFIG_KVM_ARM_PMU) += $(KVM)/arm/pmu.o kvm-$(CONFIG_KVM_ARM_NESTED_HYP) += handle_exit_nested.o +kvm-$(CONFIG_KVM_ARM_NESTED_HYP) += mmu-nested.o kvm-$(CONFIG_KVM_ARM_NESTED_HYP) += emulate-nested.o kvm-$(CONFIG_KVM_ARM_NESTED_HYP) += $(KVM)/arm/vgic/vgic-v2-nested.o diff --git a/arch/arm64/kvm/context.c b/arch/arm64/kvm/context.c index b2c0220..9ebc38f 100644 --- a/arch/arm64/kvm/context.c +++ b/arch/arm64/kvm/context.c @@ -91,7 +91,7 @@ static void create_shadow_el1_sysregs(struct kvm_vcpu *vcpu) static void setup_s2_mmu(struct kvm_vcpu *vcpu) { - struct kvm_s2_mmu *mmu = &vcpu->kvm->arch.mmu; + struct kvm_s2_mmu *mmu = vcpu_get_active_s2_mmu(vcpu); struct kvm_s2_vmid *vmid = vcpu_get_active_vmid(vcpu); vcpu->arch.hw_vttbr = kvm_get_vttbr(vmid, mmu); diff --git a/arch/arm64/kvm/mmu-nested.c b/arch/arm64/kvm/mmu-nested.c new file mode 100644 index 0000000..d52078f --- /dev/null +++ b/arch/arm64/kvm/mmu-nested.c @@ -0,0 +1,55 @@ +/* + * Copyright (C) 2016 - Columbia University + * Author: Jintack Lim <jintack@cs.columbia.edu> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/kvm_host.h> + +#include <asm/kvm_arm.h> +#include <asm/kvm_emulate.h> +#include <asm/kvm_mmu.h> +#include <asm/kvm_nested.h> + +struct kvm_nested_s2_mmu *get_nested_mmu(struct kvm_vcpu *vcpu, u64 vttbr) +{ + struct kvm_nested_s2_mmu *mmu; + u64 target_vmid = get_vmid(vttbr); + struct list_head *nested_mmu_list = &vcpu->kvm->arch.nested_mmu_list; + + list_for_each_entry_rcu(mmu, nested_mmu_list, list) { + u64 vmid = get_vmid(mmu->virtual_vttbr); + + if (target_vmid == vmid) + return mmu; + } + return NULL; +} + +struct kvm_s2_mmu *vcpu_get_active_s2_mmu(struct kvm_vcpu *vcpu) +{ + struct kvm_nested_s2_mmu *nested_mmu; + + /* If we are NOT entering the nested VM, return mmu in kvm_arch */ + if (vcpu_mode_el2(vcpu) || !vcpu_nested_stage2_enabled(vcpu)) + return &vcpu->kvm->arch.mmu; + + /* Otherwise, search for nested_mmu in the list */ + nested_mmu = get_nested_mmu(vcpu, vcpu_el2_reg(vcpu, VTTBR_EL2)); + + /* When this function is called, nested_mmu should be in the list */ + BUG_ON(!nested_mmu); + + return &nested_mmu->mmu; +}
Add the shadow stage-2 MMU context to be used for the nesting, but don't do anything with it yet. The host hypervisor maintains mmu structures for each nested VM. When entering a nested VM, the host hypervisor searches for the nested VM's mmu using vmid as a key. Note that this vmid is from the guest hypervisor's point of view. Signed-off-by: Jintack Lim <jintack@cs.columbia.edu> --- arch/arm/include/asm/kvm_host.h | 3 ++ arch/arm/kvm/arm.c | 1 + arch/arm64/include/asm/kvm_emulate.h | 13 ++++----- arch/arm64/include/asm/kvm_host.h | 19 +++++++++++++ arch/arm64/include/asm/kvm_mmu.h | 31 ++++++++++++++++++++ arch/arm64/kvm/Makefile | 1 + arch/arm64/kvm/context.c | 2 +- arch/arm64/kvm/mmu-nested.c | 55 ++++++++++++++++++++++++++++++++++++ 8 files changed, 116 insertions(+), 9 deletions(-) create mode 100644 arch/arm64/kvm/mmu-nested.c