| Message ID | 20230127112934.2749592-1-apatel@ventanamicro.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] RISC-V: KVM: Redirect illegal instruction traps to guest | expand |
On Fri, Jan 27, 2023 at 04:59:34PM +0530, Anup Patel wrote: > From: Andy Chiu <andy.chiu@sifive.com> > > The M-mode redirects an unhandled illegal instruction trap back > to S-mode. However, KVM running in HS-mode terminates the VS-mode > software when it receives illegal instruction trap. Instead, KVM > should redirect the illegal instruction trap back to VS-mode, and > let VS-mode trap handler decide the next step. This futher allows > guest kernel to implement on-demand enabling of vector extension > for a guest user space process upon first-use. > > Signed-off-by: Andy Chiu <andy.chiu@sifive.com> > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > --- > arch/riscv/kvm/vcpu_exit.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c > index c9f741ab26f5..4ea101a73d8b 100644 > --- a/arch/riscv/kvm/vcpu_exit.c > +++ b/arch/riscv/kvm/vcpu_exit.c > @@ -160,6 +160,9 @@ void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu, > > /* Set Guest PC to Guest exception vector */ > vcpu->arch.guest_context.sepc = csr_read(CSR_VSTVEC); > + > + /* Set Guest privilege mode to supervisor */ > + vcpu->arch.guest_context.sstatus |= SR_SPP; This could/should be a separate fix patch, right? > } > > /* > @@ -179,6 +182,12 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, > ret = -EFAULT; > run->exit_reason = KVM_EXIT_UNKNOWN; > switch (trap->scause) { > + case EXC_INST_ILLEGAL: > + if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) { > + kvm_riscv_vcpu_trap_redirect(vcpu, trap); > + ret = 1; > + } > + break; > case EXC_VIRTUAL_INST_FAULT: > if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) > ret = kvm_riscv_vcpu_virtual_insn(vcpu, run, trap); > -- > 2.34.1 > Otherwise, Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Thanks, drew
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c index c9f741ab26f5..4ea101a73d8b 100644 --- a/arch/riscv/kvm/vcpu_exit.c +++ b/arch/riscv/kvm/vcpu_exit.c @@ -160,6 +160,9 @@ void kvm_riscv_vcpu_trap_redirect(struct kvm_vcpu *vcpu, /* Set Guest PC to Guest exception vector */ vcpu->arch.guest_context.sepc = csr_read(CSR_VSTVEC); + + /* Set Guest privilege mode to supervisor */ + vcpu->arch.guest_context.sstatus |= SR_SPP; } /* @@ -179,6 +182,12 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct kvm_run *run, ret = -EFAULT; run->exit_reason = KVM_EXIT_UNKNOWN; switch (trap->scause) { + case EXC_INST_ILLEGAL: + if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) { + kvm_riscv_vcpu_trap_redirect(vcpu, trap); + ret = 1; + } + break; case EXC_VIRTUAL_INST_FAULT: if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV) ret = kvm_riscv_vcpu_virtual_insn(vcpu, run, trap);