| Message ID | 1500397144-16232-23-git-send-email-jintack.lim@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Jul 18, 2017 at 11:58:48AM -0500, Jintack Lim wrote: > VMs used to execute hvc #0 for the psci call if EL3 is not implemented. > However, when we come to provide the virtual EL2 mode to the VM, the > host OS inside the VM calls kvm_call_hyp() which is also hvc #0. So, > it's hard to differentiate between them from the host hypervisor's point > of view. This is a bit confusing. I think you should just refer to the fact that the architecture requires HVC calls to be handled at EL2, and when emulating EL2 inside the VM, HVC calls from the VM are handled by the VM itself, and therefore we add the support for SMC as the conduit for PSCI calls. > > So, let the VM execute smc instruction for the psci call. On ARMv8.3, > even if EL3 is not implemented, a smc instruction executed at non-secure > EL1 is trapped to EL2 if HCR_EL2.TSC==1, rather than being treated as > UNDEFINED. So, the host hypervisor can handle this psci call without any > confusion. > > Signed-off-by: Jintack Lim <jintack.lim@linaro.org> > --- > arch/arm64/kvm/handle_exit.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index d19e253..6cf6b93 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -53,8 +53,28 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) > > static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) > { > - kvm_inject_undefined(vcpu); > - return 1; > + int ret; > + > + /* If imm is non-zero, it's not defined */ > + if (kvm_vcpu_hvc_get_imm(vcpu)) { > + kvm_inject_undefined(vcpu); > + return 1; > + } > + > + /* > + * If imm is zero, it's a psci call. That's only a necessary, but not sufficient requirement. So we should say, it may be a PSCI call or we check if it's a PSCI call... > + * Note that on ARMv8.3, even if EL3 is not implemented, SMC executed > + * at Non-secure EL1 is trapped to EL2 if HCR_EL2.TSC==1, rather than > + * being treated as UNDEFINED. > + */ > + ret = kvm_psci_call(vcpu); > + if (ret < 0) { > + kvm_inject_undefined(vcpu); > + return 1; > + } > + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); > + > + return ret; > } > > /* > -- > 1.9.1 > Thanks, -Christoffer
diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c index d19e253..6cf6b93 100644 --- a/arch/arm64/kvm/handle_exit.c +++ b/arch/arm64/kvm/handle_exit.c @@ -53,8 +53,28 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) { - kvm_inject_undefined(vcpu); - return 1; + int ret; + + /* If imm is non-zero, it's not defined */ + if (kvm_vcpu_hvc_get_imm(vcpu)) { + kvm_inject_undefined(vcpu); + return 1; + } + + /* + * If imm is zero, it's a psci call. + * Note that on ARMv8.3, even if EL3 is not implemented, SMC executed + * at Non-secure EL1 is trapped to EL2 if HCR_EL2.TSC==1, rather than + * being treated as UNDEFINED. + */ + ret = kvm_psci_call(vcpu); + if (ret < 0) { + kvm_inject_undefined(vcpu); + return 1; + } + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); + + return ret; } /*
VMs used to execute hvc #0 for the psci call if EL3 is not implemented. However, when we come to provide the virtual EL2 mode to the VM, the host OS inside the VM calls kvm_call_hyp() which is also hvc #0. So, it's hard to differentiate between them from the host hypervisor's point of view. So, let the VM execute smc instruction for the psci call. On ARMv8.3, even if EL3 is not implemented, a smc instruction executed at non-secure EL1 is trapped to EL2 if HCR_EL2.TSC==1, rather than being treated as UNDEFINED. So, the host hypervisor can handle this psci call without any confusion. Signed-off-by: Jintack Lim <jintack.lim@linaro.org> --- arch/arm64/kvm/handle_exit.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-)