Commit 6b7b282e authored by Andrew Jones's avatar Andrew Jones Committed by Anup Patel
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RISC-V: KVM: Fix sbiret init before forwarding to userspace 



When forwarding SBI calls to userspace ensure sbiret.error is
initialized to SBI_ERR_NOT_SUPPORTED first, in case userspace
neglects to set it to anything. If userspace neglects it then we
can't be sure it did anything else either, so we just report it
didn't do or try anything. Just init sbiret.value to zero, which is
the preferred value to return when nothing special is specified.

KVM was already initializing both sbiret.error and sbiret.value, but
the values used appear to come from a copy+paste of the __sbi_ecall()
implementation, i.e. a0 and a1, which don't apply prior to the call
being executed, nor at all when forwarding to userspace.

Fixes: dea8ee31 ("RISC-V: KVM: Add SBI v0.1 support")
Signed-off-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240807154943.150540-2-ajones@ventanamicro.com


Signed-off-by: default avatarAnup Patel <anup@brainfault.org>
parent 47ac09b9

arch/riscv/kvm/vcpu_sbi.c

+2 −2
Original line number Diff line number Diff line
@@ -127,8 +127,8 @@ void kvm_riscv_vcpu_sbi_forward(struct kvm_vcpu *vcpu, struct kvm_run *run) 
	run->riscv_sbi.args[3] = cp->a3;

	run->riscv_sbi.args[4] = cp->a4;

	run->riscv_sbi.args[5] = cp->a5;

	run->riscv_sbi.ret[0] = cp->a0;

	run->riscv_sbi.ret[1] = cp->a1;

	run->riscv_sbi.ret[0] = SBI_ERR_NOT_SUPPORTED;

	run->riscv_sbi.ret[1] = 0;

}



void kvm_riscv_vcpu_sbi_system_reset(struct kvm_vcpu *vcpu,