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RISC-V: KVM: Fix sbiret init before forwarding to userspace

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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: dea8ee31a0 ("RISC-V: KVM: Add SBI v0.1 support")
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240807154943.150540-2-ajones@ventanamicro.com
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Andrew Jones 2024-08-07 17:49:44 +02:00 committed by Anup Patel
parent 47ac09b91b
commit 6b7b282e6b
1 changed files with 2 additions and 2 deletions
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4
arch/riscv/kvm/vcpu_sbi.c
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@ -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,