Commit cdeb59bb authored by Andy Chiu's avatar Andy Chiu Committed by Anup Patel
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RISC-V: KVM: Redirect illegal instruction traps to guest 



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: default avatarAndy Chiu <andy.chiu@sifive.com>
Signed-off-by: default avatarAnup Patel <apatel@ventanamicro.com>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Reviewed-by: default avatarAtish Patra <atishp@rivosinc.com>
Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent 06723e12

arch/riscv/kvm/vcpu_exit.c

+6 −0
Original line number Diff line number Diff line
@@ -182,6 +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);