[PATCH v4 01/30] KVM: x86: Extract REGS and SREGS runtime sync code to helpers

[Sean Christopherson <seanjc@google.com>]

Extract the REGS and SREGS portions of {store,sync}_regs() into separate
helpers in anticipation of moving the register specific code out of x86.c
and into regs.c.

No functional change intended.

Cc: Yosry Ahmed <yosry@kernel.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/x86.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cf122b8c3210..74b8f98dcb24 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12687,7 +12687,7 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
 	return 0;
 }
 
-static void store_regs(struct kvm_vcpu *vcpu)
+static void kvm_run_sync_regs_to_user(struct kvm_vcpu *vcpu)
 {
 	BUILD_BUG_ON(sizeof(struct kvm_sync_regs) > SYNC_REGS_SIZE_BYTES);
 
@@ -12696,13 +12696,18 @@ static void store_regs(struct kvm_vcpu *vcpu)
 
 	if (vcpu->run->kvm_valid_regs & KVM_SYNC_X86_SREGS)
 		__get_sregs(vcpu, &vcpu->run->s.regs.sregs);
+}
+
+static void store_regs(struct kvm_vcpu *vcpu)
+{
+	kvm_run_sync_regs_to_user(vcpu);
 
 	if (vcpu->run->kvm_valid_regs & KVM_SYNC_X86_EVENTS)
 		kvm_vcpu_ioctl_x86_get_vcpu_events(
 				vcpu, &vcpu->run->s.regs.events);
 }
 
-static int sync_regs(struct kvm_vcpu *vcpu)
+static int kvm_run_sync_regs_from_user(struct kvm_vcpu *vcpu)
 {
 	if (vcpu->run->kvm_dirty_regs & KVM_SYNC_X86_REGS) {
 		__set_regs(vcpu, &vcpu->run->s.regs.regs);
@@ -12718,6 +12723,14 @@ static int sync_regs(struct kvm_vcpu *vcpu)
 		vcpu->run->kvm_dirty_regs &= ~KVM_SYNC_X86_SREGS;
 	}
 
+	return 0;
+}
+
+static int sync_regs(struct kvm_vcpu *vcpu)
+{
+	if (kvm_run_sync_regs_from_user(vcpu))
+		return -EINVAL;
+
 	if (vcpu->run->kvm_dirty_regs & KVM_SYNC_X86_EVENTS) {
 		struct kvm_vcpu_events events = vcpu->run->s.regs.events;
 
-- 
2.54.0.1136.gdb2ca164c4-goog