| Message ID | 20230803140022.399333-7-dbarboza@ventanamicro.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | RISC-V: KVM: change get_reg/set_reg error codes | expand |
diff --git a/arch/riscv/kvm/vcpu_onereg.c b/arch/riscv/kvm/vcpu_onereg.c index 0cf25c18b582..e752e2dca8ed 100644 --- a/arch/riscv/kvm/vcpu_onereg.c +++ b/arch/riscv/kvm/vcpu_onereg.c @@ -190,6 +190,13 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu, if (fls(reg_val) >= RISCV_ISA_EXT_BASE) return -EINVAL; + /* + * Return early (i.e. do nothing) if reg_val is the same + * value retrievable via kvm_riscv_vcpu_get_reg_config(). + */ + if (reg_val == (vcpu->arch.isa[0] & KVM_RISCV_BASE_ISA_MASK)) + break; + if (!vcpu->arch.ran_atleast_once) { /* Ignore the enable/disable request for certain extensions */ for (i = 0; i < RISCV_ISA_EXT_BASE; i++) {
kvm_riscv_vcpu_set_reg_config() will return -EBUSY if the ISA config reg is being written after the VCPU ran at least once. The same restriction isn't placed in kvm_riscv_vcpu_get_reg_config(), so there's a chance that we'll -EBUSY out on an ISA config reg write even if the userspace intended no changes to it. We'll allow the same form of 'lazy writing' that registers such as zicbom/zicboz_block_size supports: avoid erroring out if userspace made no changes to the ISA config reg. Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> --- arch/riscv/kvm/vcpu_onereg.c | 7 +++++++ 1 file changed, 7 insertions(+)