[PATCH 6.18.y 1/4] KVM: x86: Extract REGS and SREGS runtime sync code to helpers

[Sasha Levin <sashal@kernel.org>]

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 6a8a98aa9c147eb63f5a360f157f207bf46c05ee ]

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>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Message-ID: <20260613000329.732085-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Stable-dep-of: 184bd464bdb6 ("KVM: x86: Check EFER validity on KVM_SET_SREGS*")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 f0707f0e1ec00..7f27c80190f89 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12629,7 +12629,7 @@ 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);
 
@@ -12638,13 +12638,18 @@ 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);
@@ -12660,6 +12665,14 @@ 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;
 
-- 
2.53.0