| Message ID | 20190621093843.220980-28-marc.zyngier@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: arm64: ARMv8.3 Nested Virtualization support | expand |
On 06/21/2019 10:38 AM, Marc Zyngier wrote: > From: Jintack Lim <jintack.lim@linaro.org> > > Forward the EL1 virtual memory register traps to the virtual EL2 if they > are not coming from the virtual EL2 and the virtual HCR_EL2.TVM or TRVM > bit is set. > > This is for recursive nested virtualization. > > Signed-off-by: Jintack Lim <jintack.lim@linaro.org> > Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> > --- > arch/arm64/kvm/sys_regs.c | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 582d62aa48b7..0f74b9277a86 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -436,6 +436,27 @@ static bool access_dcsw(struct kvm_vcpu *vcpu, > return true; > } > > +/* This function is to support the recursive nested virtualization */ > +static bool forward_vm_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p) > +{ > + u64 hcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2); > + > + /* If a trap comes from the virtual EL2, the host hypervisor handles. */ > + if (vcpu_mode_el2(vcpu)) > + return false; > + > + /* > + * If the virtual HCR_EL2.TVM or TRVM bit is set, we need to foward > + * this trap to the virtual EL2. > + */ > + if ((hcr_el2 & HCR_TVM) && p->is_write) > + return true; > + else if ((hcr_el2 & HCR_TRVM) && !p->is_write) > + return true; > + > + return false; > +} > + > /* > * Generic accessor for VM registers. Only called as long as HCR_TVM > * is set. If the guest enables the MMU, we stop trapping the VM > @@ -452,6 +473,9 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu, > if (el12_reg(p) && forward_nv_traps(vcpu)) > return false; > > + if (!el12_reg(p) && forward_vm_traps(vcpu, p)) > + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu)); Since we already have forward_traps(), isn't this just: if (!el12_reg(p) && forward_traps(vcpu, p->is_write ? HCR_TVM : HCR_TRVM)) return true; We could maybe simplify forward_vm_traps() to just call forward_traps() similar to forward_nv_traps(). Cheers, Julien
On 26/06/2019 07:55, Julien Thierry wrote: > > > On 06/21/2019 10:38 AM, Marc Zyngier wrote: >> From: Jintack Lim <jintack.lim@linaro.org> >> >> Forward the EL1 virtual memory register traps to the virtual EL2 if they >> are not coming from the virtual EL2 and the virtual HCR_EL2.TVM or TRVM >> bit is set. >> >> This is for recursive nested virtualization. >> >> Signed-off-by: Jintack Lim <jintack.lim@linaro.org> >> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> >> --- >> arch/arm64/kvm/sys_regs.c | 24 ++++++++++++++++++++++++ >> 1 file changed, 24 insertions(+) >> >> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c >> index 582d62aa48b7..0f74b9277a86 100644 >> --- a/arch/arm64/kvm/sys_regs.c >> +++ b/arch/arm64/kvm/sys_regs.c >> @@ -436,6 +436,27 @@ static bool access_dcsw(struct kvm_vcpu *vcpu, >> return true; >> } >> >> +/* This function is to support the recursive nested virtualization */ >> +static bool forward_vm_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p) >> +{ >> + u64 hcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2); >> + >> + /* If a trap comes from the virtual EL2, the host hypervisor handles. */ >> + if (vcpu_mode_el2(vcpu)) >> + return false; >> + >> + /* >> + * If the virtual HCR_EL2.TVM or TRVM bit is set, we need to foward >> + * this trap to the virtual EL2. >> + */ >> + if ((hcr_el2 & HCR_TVM) && p->is_write) >> + return true; >> + else if ((hcr_el2 & HCR_TRVM) && !p->is_write) >> + return true; >> + >> + return false; >> +} >> + >> /* >> * Generic accessor for VM registers. Only called as long as HCR_TVM >> * is set. If the guest enables the MMU, we stop trapping the VM >> @@ -452,6 +473,9 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu, >> if (el12_reg(p) && forward_nv_traps(vcpu)) >> return false; >> >> + if (!el12_reg(p) && forward_vm_traps(vcpu, p)) >> + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu)); > > Since we already have forward_traps(), isn't this just: > > if (!el12_reg(p) && forward_traps(vcpu, p->is_write ? HCR_TVM : HCR_TRVM)) > return true; > > We could maybe simplify forward_vm_traps() to just call forward_traps() > similar to forward_nv_traps(). Odd. I remember doing something like that. Where has it gone? Yes, this looks sensible. Thanks, M.
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 582d62aa48b7..0f74b9277a86 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -436,6 +436,27 @@ static bool access_dcsw(struct kvm_vcpu *vcpu, return true; } +/* This function is to support the recursive nested virtualization */ +static bool forward_vm_traps(struct kvm_vcpu *vcpu, struct sys_reg_params *p) +{ + u64 hcr_el2 = __vcpu_sys_reg(vcpu, HCR_EL2); + + /* If a trap comes from the virtual EL2, the host hypervisor handles. */ + if (vcpu_mode_el2(vcpu)) + return false; + + /* + * If the virtual HCR_EL2.TVM or TRVM bit is set, we need to foward + * this trap to the virtual EL2. + */ + if ((hcr_el2 & HCR_TVM) && p->is_write) + return true; + else if ((hcr_el2 & HCR_TRVM) && !p->is_write) + return true; + + return false; +} + /* * Generic accessor for VM registers. Only called as long as HCR_TVM * is set. If the guest enables the MMU, we stop trapping the VM @@ -452,6 +473,9 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu, if (el12_reg(p) && forward_nv_traps(vcpu)) return false; + if (!el12_reg(p) && forward_vm_traps(vcpu, p)) + return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_hsr(vcpu)); + BUG_ON(!vcpu_mode_el2(vcpu) && !p->is_write); if (!p->is_write) {