[PATCH v7 2/6] KVM: x86: Create helper methods for KVM_{GET,SET}_CLOCK ioctls

From: Oliver Upton <oupton@google.com>
To: kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Marc Zyngier <maz@kernel.org>, Peter Shier <pshier@google.com>,
	Jim Mattson <jmattson@google.com>,
	David Matlack <dmatlack@google.com>,
	Ricardo Koller <ricarkol@google.com>,
	Jing Zhang <jingzhangos@google.com>,
	Raghavendra Rao Anata <rananta@google.com>,
	James Morse <james.morse@arm.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	Andrew Jones <drjones@redhat.com>, Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Oliver Upton <oupton@google.com>
Subject: [PATCH v7 2/6] KVM: x86: Create helper methods for KVM_{GET,SET}_CLOCK ioctls
Date: Mon, 16 Aug 2021 00:11:26 +0000	[thread overview]
Message-ID: <20210816001130.3059564-3-oupton@google.com> (raw)
In-Reply-To: <20210816001130.3059564-1-oupton@google.com>

Wrap the existing implementation of the KVM_{GET,SET}_CLOCK ioctls in
helper methods.

No functional change intended.

Signed-off-by: Oliver Upton <oupton@google.com>
---
 arch/x86/kvm/x86.c | 107 ++++++++++++++++++++++++---------------------
 1 file changed, 57 insertions(+), 50 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2f3929bd5f58..39eaa2fb2001 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5833,12 +5833,65 @@ int kvm_arch_pm_notifier(struct kvm *kvm, unsigned long state)
 }
 #endif /* CONFIG_HAVE_KVM_PM_NOTIFIER */
 
+static int kvm_vm_ioctl_get_clock(struct kvm *kvm, void __user *argp)
+{
+	struct kvm_clock_data data;
+
+	/*
+	 * Zero flags as it is accessed RMW, leave everything else
+	 * uninitialized as clock is always written and no other fields
+	 * are consumed.
+	 */
+	data.flags = 0;
+	get_kvmclock(kvm, &data);
+	memset(&data.pad, 0, sizeof(data.pad));
+
+	if (copy_to_user(argp, &data, sizeof(data)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static int kvm_vm_ioctl_set_clock(struct kvm *kvm, void __user *argp)
+{
+	struct kvm_arch *ka = &kvm->arch;
+	struct kvm_clock_data data;
+	u64 now_ns;
+
+	if (copy_from_user(&data, argp, sizeof(data)))
+		return -EFAULT;
+
+	if (data.flags)
+		return -EINVAL;
+
+	kvm_hv_invalidate_tsc_page(kvm);
+	kvm_start_pvclock_update(kvm);
+	pvclock_update_vm_gtod_copy(kvm);
+
+	/*
+	 * This pairs with kvm_guest_time_update(): when masterclock is
+	 * in use, we use master_kernel_ns + kvmclock_offset to set
+	 * unsigned 'system_time' so if we use get_kvmclock_ns() (which
+	 * is slightly ahead) here we risk going negative on unsigned
+	 * 'system_time' when 'data.clock' is very small.
+	 */
+	if (kvm->arch.use_master_clock)
+		now_ns = ka->master_kernel_ns;
+	else
+		now_ns = get_kvmclock_base_ns();
+	ka->kvmclock_offset = data.clock - now_ns;
+	kvm_end_pvclock_update(kvm);
+
+	return 0;
+}
+
 long kvm_arch_vm_ioctl(struct file *filp,
 		       unsigned int ioctl, unsigned long arg)
 {
 	struct kvm *kvm = filp->private_data;
 	void __user *argp = (void __user *)arg;
 	int r = -ENOTTY;
+
 	/*
 	 * This union makes it completely explicit to gcc-3.x
 	 * that these two variables' stack usage should be
@@ -6076,58 +6129,12 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		break;
 	}
 #endif
-	case KVM_SET_CLOCK: {
-		struct kvm_arch *ka = &kvm->arch;
-		struct kvm_clock_data user_ns;
-		u64 now_ns;
-
-		r = -EFAULT;
-		if (copy_from_user(&user_ns, argp, sizeof(user_ns)))
-			goto out;
-
-		r = -EINVAL;
-		if (user_ns.flags)
-			goto out;
-
-		r = 0;
-
-		kvm_hv_invalidate_tsc_page(kvm);
-		kvm_start_pvclock_update(kvm);
-		pvclock_update_vm_gtod_copy(kvm);
-
-		/*
-		 * This pairs with kvm_guest_time_update(): when masterclock is
-		 * in use, we use master_kernel_ns + kvmclock_offset to set
-		 * unsigned 'system_time' so if we use get_kvmclock_ns() (which
-		 * is slightly ahead) here we risk going negative on unsigned
-		 * 'system_time' when 'user_ns.clock' is very small.
-		 */
-		if (kvm->arch.use_master_clock)
-			now_ns = ka->master_kernel_ns;
-		else
-			now_ns = get_kvmclock_base_ns();
-		ka->kvmclock_offset = user_ns.clock - now_ns;
-		kvm_end_pvclock_update(kvm);
+	case KVM_SET_CLOCK:
+		r = kvm_vm_ioctl_set_clock(kvm, argp);
 		break;
-	}
-	case KVM_GET_CLOCK: {
-		struct kvm_clock_data user_ns;
-
-		/*
-		 * Zero flags as it is accessed RMW, leave everything else
-		 * uninitialized as clock is always written and no other fields
-		 * are consumed.
-		 */
-		user_ns.flags = 0;
-		get_kvmclock(kvm, &user_ns);
-		memset(&user_ns.pad, 0, sizeof(user_ns.pad));
-
-		r = -EFAULT;
-		if (copy_to_user(argp, &user_ns, sizeof(user_ns)))
-			goto out;
-		r = 0;
+	case KVM_GET_CLOCK:
+		r = kvm_vm_ioctl_get_clock(kvm, argp);
 		break;
-	}
 	case KVM_MEMORY_ENCRYPT_OP: {
 		r = -ENOTTY;
 		if (kvm_x86_ops.mem_enc_op)
-- 
2.33.0.rc1.237.g0d66db33f3-goog

