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Subject[RFC PATCH v3 10/59] KVM: x86: Split core of hypercall emulation to helper function
Date
From: Sean Christopherson <sean.j.christopherson@intel.com>

By necessity, TDX will use a different register ABI for hypercalls.
Break out the core functionality so that it may be reused for TDX.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
arch/x86/include/asm/kvm_host.h | 4 +++
arch/x86/kvm/x86.c | 55 ++++++++++++++++++++-------------
2 files changed, 38 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e5d8700319cc..5b31d8e5fcbf 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1778,6 +1778,10 @@ void kvm_request_apicv_update(struct kvm *kvm, bool activate,
void __kvm_request_apicv_update(struct kvm *kvm, bool activate,
unsigned long bit);

+unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr,
+ unsigned long a0, unsigned long a1,
+ unsigned long a2, unsigned long a3,
+ int op_64_bit);
int kvm_emulate_hypercall(struct kvm_vcpu *vcpu);

int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 error_code,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index dc7eb5fddfd3..8a4774c5c85d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8829,26 +8829,15 @@ static int complete_hypercall_exit(struct kvm_vcpu *vcpu)
return kvm_skip_emulated_instruction(vcpu);
}

-int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
+unsigned long __kvm_emulate_hypercall(struct kvm_vcpu *vcpu, unsigned long nr,
+ unsigned long a0, unsigned long a1,
+ unsigned long a2, unsigned long a3,
+ int op_64_bit)
{
- unsigned long nr, a0, a1, a2, a3, ret;
- int op_64_bit;
-
- 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);
+ unsigned long ret;

trace_kvm_hypercall(nr, a0, a1, a2, a3);

- op_64_bit = is_64_bit_mode(vcpu);
if (!op_64_bit) {
nr &= 0xFFFFFFFF;
a0 &= 0xFFFFFFFF;
@@ -8857,11 +8846,6 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
a3 &= 0xFFFFFFFF;
}

- if (static_call(kvm_x86_get_cpl)(vcpu) != 0) {
- ret = -KVM_EPERM;
- goto out;
- }
-
ret = -KVM_ENOSYS;

switch (nr) {
@@ -8920,6 +8904,35 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
ret = -KVM_ENOSYS;
break;
}
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__kvm_emulate_hypercall);
+
+int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)
+{
+ unsigned long nr, a0, a1, a2, a3, ret;
+ int op_64_bit;
+
+ 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_mode(vcpu);
+
+ if (static_call(kvm_x86_get_cpl)(vcpu) != 0) {
+ ret = -KVM_EPERM;
+ goto out;
+ }
+
+ ret = __kvm_emulate_hypercall(vcpu, nr, a0, a1, a2, a3, op_64_bit);
out:
if (!op_64_bit)
ret = (u32)ret;
--
2.25.1
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