| Message ID | 20180215210332.8648-34-christoffer.dall@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, 15 Feb 2018 21:03:25 +0000, Christoffer Dall wrote: > > We do not have to change the c15 trap setting on each switch to/from the > guest on VHE systems, because this setting only affects EL0. Did you mean EL1 instead? > > The PMU and debug trap configuration can also be done on vcpu load/put > instead, because they don't affect how the host kernel can access the > debug registers while executing KVM kernel code. > > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> > --- > arch/arm64/include/asm/kvm_hyp.h | 3 +++ > arch/arm64/kvm/hyp/switch.c | 31 ++++++++++++++++++++++--------- > arch/arm64/kvm/hyp/sysreg-sr.c | 4 ++++ > 3 files changed, 29 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h > index 2b1fda90dde4..949f2e77ae58 100644 > --- a/arch/arm64/include/asm/kvm_hyp.h > +++ b/arch/arm64/include/asm/kvm_hyp.h > @@ -147,6 +147,9 @@ void __fpsimd_save_state(struct user_fpsimd_state *fp_regs); > void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs); > bool __fpsimd_enabled(void); > > +void activate_traps_vhe_load(struct kvm_vcpu *vcpu); > +void deactivate_traps_vhe_put(void); > + > u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt); > void __noreturn __hyp_do_panic(unsigned long, ...); > > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c > index 9c40e203bd09..5e94955b89ea 100644 > --- a/arch/arm64/kvm/hyp/switch.c > +++ b/arch/arm64/kvm/hyp/switch.c > @@ -101,6 +101,8 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) > { > u64 val; > > + __activate_traps_common(vcpu); > + > val = CPTR_EL2_DEFAULT; > val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ; > write_sysreg(val, cptr_el2); > @@ -120,20 +122,12 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) > write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2); > > __activate_traps_fpsimd32(vcpu); > - __activate_traps_common(vcpu); > __activate_traps_arch()(vcpu); > } > > static void __hyp_text __deactivate_traps_vhe(void) > { > extern char vectors[]; /* kernel exception vectors */ > - u64 mdcr_el2 = read_sysreg(mdcr_el2); > - > - mdcr_el2 &= MDCR_EL2_HPMN_MASK | > - MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT | > - MDCR_EL2_TPMS; > - > - write_sysreg(mdcr_el2, mdcr_el2); > write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); > write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); > write_sysreg(vectors, vbar_el1); > @@ -143,6 +137,8 @@ static void __hyp_text __deactivate_traps_nvhe(void) > { > u64 mdcr_el2 = read_sysreg(mdcr_el2); > > + __deactivate_traps_common(); > + > mdcr_el2 &= MDCR_EL2_HPMN_MASK; > mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT; > > @@ -166,10 +162,27 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) > if (vcpu->arch.hcr_el2 & HCR_VSE) > vcpu->arch.hcr_el2 = read_sysreg(hcr_el2); > > - __deactivate_traps_common(); > __deactivate_traps_arch()(); > } > > +void activate_traps_vhe_load(struct kvm_vcpu *vcpu) > +{ > + __activate_traps_common(vcpu); > +} > + > +void deactivate_traps_vhe_put(void) > +{ > + u64 mdcr_el2 = read_sysreg(mdcr_el2); > + > + mdcr_el2 &= MDCR_EL2_HPMN_MASK | > + MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT | > + MDCR_EL2_TPMS; > + > + write_sysreg(mdcr_el2, mdcr_el2); > + > + __deactivate_traps_common(); > +} > + > static void __hyp_text __activate_vm(struct kvm *kvm) > { > write_sysreg(kvm->arch.vttbr, vttbr_el2); > diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c > index aacba4636871..b3894df6bf1a 100644 > --- a/arch/arm64/kvm/hyp/sysreg-sr.c > +++ b/arch/arm64/kvm/hyp/sysreg-sr.c > @@ -254,6 +254,8 @@ void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) > __sysreg_restore_el1_state(guest_ctxt); > > vcpu->arch.sysregs_loaded_on_cpu = true; > + > + activate_traps_vhe_load(vcpu); > } > > /** > @@ -275,6 +277,8 @@ void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) > if (!has_vhe()) > return; > > + deactivate_traps_vhe_put(); > + > __sysreg_save_el1_state(guest_ctxt); > __sysreg_save_user_state(guest_ctxt); > __sysreg32_save_state(vcpu); > -- > 2.14.2 > I must admit that I find these two layers of trap configuration mildly confusing. I can see why it is done like this (there is hardly any other way), but still... Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> M.
On Thu, Feb 15, 2018 at 10:03:25PM +0100, Christoffer Dall wrote: > We do not have to change the c15 trap setting on each switch to/from the > guest on VHE systems, because this setting only affects EL0. > > The PMU and debug trap configuration can also be done on vcpu load/put > instead, because they don't affect how the host kernel can access the > debug registers while executing KVM kernel code. > > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> > --- > arch/arm64/include/asm/kvm_hyp.h | 3 +++ > arch/arm64/kvm/hyp/switch.c | 31 ++++++++++++++++++++++--------- > arch/arm64/kvm/hyp/sysreg-sr.c | 4 ++++ > 3 files changed, 29 insertions(+), 9 deletions(-) > The last patch 32/40 probably should have been closer to 13/40 in this series. That would allow this patch to directly follow it's preparatory patch 31/40, but I'm just whiny reviewer... Reviewed-by: Andrew Jones <drjones@redhat.com>
On Wed, Feb 21, 2018 at 06:20:54PM +0000, Marc Zyngier wrote: > On Thu, 15 Feb 2018 21:03:25 +0000, > Christoffer Dall wrote: > > > > We do not have to change the c15 trap setting on each switch to/from the > > guest on VHE systems, because this setting only affects EL0. > > Did you mean EL1 instead? > Not sure what I meant, but HSTR_EL2 appears to affect EL1 and EL0, and the PMU configuration we can do on vcpu_load on VHE systems is only about EL0 as far as I can tell. > > > > The PMU and debug trap configuration can also be done on vcpu load/put > > instead, because they don't affect how the host kernel can access the > > debug registers while executing KVM kernel code. > > > > Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> > > --- > > arch/arm64/include/asm/kvm_hyp.h | 3 +++ > > arch/arm64/kvm/hyp/switch.c | 31 ++++++++++++++++++++++--------- > > arch/arm64/kvm/hyp/sysreg-sr.c | 4 ++++ > > 3 files changed, 29 insertions(+), 9 deletions(-) > > > > diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h > > index 2b1fda90dde4..949f2e77ae58 100644 > > --- a/arch/arm64/include/asm/kvm_hyp.h > > +++ b/arch/arm64/include/asm/kvm_hyp.h > > @@ -147,6 +147,9 @@ void __fpsimd_save_state(struct user_fpsimd_state *fp_regs); > > void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs); > > bool __fpsimd_enabled(void); > > > > +void activate_traps_vhe_load(struct kvm_vcpu *vcpu); > > +void deactivate_traps_vhe_put(void); > > + > > u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt); > > void __noreturn __hyp_do_panic(unsigned long, ...); > > > > diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c > > index 9c40e203bd09..5e94955b89ea 100644 > > --- a/arch/arm64/kvm/hyp/switch.c > > +++ b/arch/arm64/kvm/hyp/switch.c > > @@ -101,6 +101,8 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) > > { > > u64 val; > > > > + __activate_traps_common(vcpu); > > + > > val = CPTR_EL2_DEFAULT; > > val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ; > > write_sysreg(val, cptr_el2); > > @@ -120,20 +122,12 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) > > write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2); > > > > __activate_traps_fpsimd32(vcpu); > > - __activate_traps_common(vcpu); > > __activate_traps_arch()(vcpu); > > } > > > > static void __hyp_text __deactivate_traps_vhe(void) > > { > > extern char vectors[]; /* kernel exception vectors */ > > - u64 mdcr_el2 = read_sysreg(mdcr_el2); > > - > > - mdcr_el2 &= MDCR_EL2_HPMN_MASK | > > - MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT | > > - MDCR_EL2_TPMS; > > - > > - write_sysreg(mdcr_el2, mdcr_el2); > > write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); > > write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); > > write_sysreg(vectors, vbar_el1); > > @@ -143,6 +137,8 @@ static void __hyp_text __deactivate_traps_nvhe(void) > > { > > u64 mdcr_el2 = read_sysreg(mdcr_el2); > > > > + __deactivate_traps_common(); > > + > > mdcr_el2 &= MDCR_EL2_HPMN_MASK; > > mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT; > > > > @@ -166,10 +162,27 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) > > if (vcpu->arch.hcr_el2 & HCR_VSE) > > vcpu->arch.hcr_el2 = read_sysreg(hcr_el2); > > > > - __deactivate_traps_common(); > > __deactivate_traps_arch()(); > > } > > > > +void activate_traps_vhe_load(struct kvm_vcpu *vcpu) > > +{ > > + __activate_traps_common(vcpu); > > +} > > + > > +void deactivate_traps_vhe_put(void) > > +{ > > + u64 mdcr_el2 = read_sysreg(mdcr_el2); > > + > > + mdcr_el2 &= MDCR_EL2_HPMN_MASK | > > + MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT | > > + MDCR_EL2_TPMS; > > + > > + write_sysreg(mdcr_el2, mdcr_el2); > > + > > + __deactivate_traps_common(); > > +} > > + > > static void __hyp_text __activate_vm(struct kvm *kvm) > > { > > write_sysreg(kvm->arch.vttbr, vttbr_el2); > > diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c > > index aacba4636871..b3894df6bf1a 100644 > > --- a/arch/arm64/kvm/hyp/sysreg-sr.c > > +++ b/arch/arm64/kvm/hyp/sysreg-sr.c > > @@ -254,6 +254,8 @@ void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) > > __sysreg_restore_el1_state(guest_ctxt); > > > > vcpu->arch.sysregs_loaded_on_cpu = true; > > + > > + activate_traps_vhe_load(vcpu); > > } > > > > /** > > @@ -275,6 +277,8 @@ void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) > > if (!has_vhe()) > > return; > > > > + deactivate_traps_vhe_put(); > > + > > __sysreg_save_el1_state(guest_ctxt); > > __sysreg_save_user_state(guest_ctxt); > > __sysreg32_save_state(vcpu); > > -- > > 2.14.2 > > > > I must admit that I find these two layers of trap configuration mildly > confusing. I can see why it is done like this (there is hardly any > other way), but still... Perhaps the naming could be improved. Right now we have: _traps_common: Same code for non-VHE/VHE. Called: non-VHE: on every switch. VHE: on load/put. _traps: Same code for non-VHE/VHE. Called: VHE/non-VHE: On every switch. _traps_nvhe: Code specific to non-VHE system. Called: non-VHE: on every switch _traps_vhe: Code specific to VHE system. Called: VHE: on every switch _traps_vhe_load/put: Code specific to VHE system. Called: VHE: on vcpu load/put We could simplify this at the cost of code duplication to: _traps_nvhe _traps_vhe _traps_vhe_load/put Thoughts? > > Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> > Thanks, -Christoffer
diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index 2b1fda90dde4..949f2e77ae58 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -147,6 +147,9 @@ void __fpsimd_save_state(struct user_fpsimd_state *fp_regs); void __fpsimd_restore_state(struct user_fpsimd_state *fp_regs); bool __fpsimd_enabled(void); +void activate_traps_vhe_load(struct kvm_vcpu *vcpu); +void deactivate_traps_vhe_put(void); + u64 __guest_enter(struct kvm_vcpu *vcpu, struct kvm_cpu_context *host_ctxt); void __noreturn __hyp_do_panic(unsigned long, ...); diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 9c40e203bd09..5e94955b89ea 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -101,6 +101,8 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu) { u64 val; + __activate_traps_common(vcpu); + val = CPTR_EL2_DEFAULT; val |= CPTR_EL2_TTA | CPTR_EL2_TFP | CPTR_EL2_TZ; write_sysreg(val, cptr_el2); @@ -120,20 +122,12 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2); __activate_traps_fpsimd32(vcpu); - __activate_traps_common(vcpu); __activate_traps_arch()(vcpu); } static void __hyp_text __deactivate_traps_vhe(void) { extern char vectors[]; /* kernel exception vectors */ - u64 mdcr_el2 = read_sysreg(mdcr_el2); - - mdcr_el2 &= MDCR_EL2_HPMN_MASK | - MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT | - MDCR_EL2_TPMS; - - write_sysreg(mdcr_el2, mdcr_el2); write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2); write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1); write_sysreg(vectors, vbar_el1); @@ -143,6 +137,8 @@ static void __hyp_text __deactivate_traps_nvhe(void) { u64 mdcr_el2 = read_sysreg(mdcr_el2); + __deactivate_traps_common(); + mdcr_el2 &= MDCR_EL2_HPMN_MASK; mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT; @@ -166,10 +162,27 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu) if (vcpu->arch.hcr_el2 & HCR_VSE) vcpu->arch.hcr_el2 = read_sysreg(hcr_el2); - __deactivate_traps_common(); __deactivate_traps_arch()(); } +void activate_traps_vhe_load(struct kvm_vcpu *vcpu) +{ + __activate_traps_common(vcpu); +} + +void deactivate_traps_vhe_put(void) +{ + u64 mdcr_el2 = read_sysreg(mdcr_el2); + + mdcr_el2 &= MDCR_EL2_HPMN_MASK | + MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT | + MDCR_EL2_TPMS; + + write_sysreg(mdcr_el2, mdcr_el2); + + __deactivate_traps_common(); +} + static void __hyp_text __activate_vm(struct kvm *kvm) { write_sysreg(kvm->arch.vttbr, vttbr_el2); diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c index aacba4636871..b3894df6bf1a 100644 --- a/arch/arm64/kvm/hyp/sysreg-sr.c +++ b/arch/arm64/kvm/hyp/sysreg-sr.c @@ -254,6 +254,8 @@ void kvm_vcpu_load_sysregs(struct kvm_vcpu *vcpu) __sysreg_restore_el1_state(guest_ctxt); vcpu->arch.sysregs_loaded_on_cpu = true; + + activate_traps_vhe_load(vcpu); } /** @@ -275,6 +277,8 @@ void kvm_vcpu_put_sysregs(struct kvm_vcpu *vcpu) if (!has_vhe()) return; + deactivate_traps_vhe_put(); + __sysreg_save_el1_state(guest_ctxt); __sysreg_save_user_state(guest_ctxt); __sysreg32_save_state(vcpu);
We do not have to change the c15 trap setting on each switch to/from the guest on VHE systems, because this setting only affects EL0. The PMU and debug trap configuration can also be done on vcpu load/put instead, because they don't affect how the host kernel can access the debug registers while executing KVM kernel code. Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org> --- arch/arm64/include/asm/kvm_hyp.h | 3 +++ arch/arm64/kvm/hyp/switch.c | 31 ++++++++++++++++++++++--------- arch/arm64/kvm/hyp/sysreg-sr.c | 4 ++++ 3 files changed, 29 insertions(+), 9 deletions(-)