On 4/4/2024 2:34 AM, Isaku Yamahata wrote:
On Fri, Mar 29, 2024 at 11:24:55AM +0800,
Chao Gao <chao.gao@xxxxxxxxx> wrote:
On Mon, Feb 26, 2024 at 12:26:39AM -0800, isaku.yamahata@xxxxxxxxx wrote:
+
+int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
+{
+ unsigned long nr, a0, a1, a2, a3, ret;
+ int op_64_bit;
+ int cpl;
+
+ if (kvm_xen_hypercall_enabled(vcpu->kvm))
+ return kvm_xen_hypercall(vcpu);
+
+ if (kvm_hv_hypercall_enabled(vcpu))
+ return kvm_hv_hypercall(vcpu);
+
+ nr = kvm_rax_read(vcpu);
+ a0 = kvm_rbx_read(vcpu);
+ a1 = kvm_rcx_read(vcpu);
+ a2 = kvm_rdx_read(vcpu);
+ a3 = kvm_rsi_read(vcpu);
+ op_64_bit = is_64_bit_hypercall(vcpu);
+ cpl = static_call(kvm_x86_get_cpl)(vcpu);
+
+ ret = __kvm_emulate_hypercall(vcpu, nr, a0, a1, a2, a3, op_64_bit, cpl);
+ if (nr == KVM_HC_MAP_GPA_RANGE && !ret)
+ /* MAP_GPA tosses the request to the user space. */
no need to check what the request is. Just checking the return value will suffice.
This is needed to avoid updating rax etc. KVM_HC_MAP_GPA_RANGE is only an
exception to go to the user space. This check is a bit weird, but I couldn't
find a good way.
To be generic, I think we can use
"vcpu->kvm->arch.hypercall_exit_enabled & (1 << nr)" to check if it
needs to exit to userspace.
i.e.,
+ ...
+ ret = __kvm_emulate_hypercall(vcpu, nr, a0, a1, a2, a3,
op_64_bit, cpl);
+ if (!ret && (vcpu->kvm->arch.hypercall_exit_enabled & (1 << nr)))
+ /* The hypercall is requested to exit to userspace. */
+ return 0;
+ return 0;
+
if (!op_64_bit)
ret = (u32)ret;
kvm_rax_write(vcpu, ret);
- ++vcpu->stat.hypercalls;
return kvm_skip_emulated_instruction(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_emulate_hypercall);
--
2.25.1
