1 files changed, 129 insertions, 0 deletions
diff --git a/drivers/ptp/ptp_kvm_x86.c b/drivers/ptp/ptp_kvm_x86.c
new file mode 100644
index 0000000000..902844cc1a
--- /dev/null
+++ b/drivers/ptp/ptp_kvm_x86.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Virtual PTP 1588 clock for use with KVM guests
+ *
+ * Copyright (C) 2017 Red Hat Inc.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <asm/pvclock.h>
+#include <asm/kvmclock.h>
+#include <linux/module.h>
+#include <uapi/asm/kvm_para.h>
+#include <uapi/linux/kvm_para.h>
+#include <linux/ptp_clock_kernel.h>
+#include <linux/ptp_kvm.h>
+#include <linux/set_memory.h>
+
+static phys_addr_t clock_pair_gpa;
+static struct kvm_clock_pairing clock_pair_glbl;
+static struct kvm_clock_pairing *clock_pair;
+
+int kvm_arch_ptp_init(void)
+{
+	struct page *p;
+	long ret;
+
+	if (!kvm_para_available())
+		return -ENODEV;
+
+	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
+		p = alloc_page(GFP_KERNEL | __GFP_ZERO);
+		if (!p)
+			return -ENOMEM;
+
+		clock_pair = page_address(p);
+		ret = set_memory_decrypted((unsigned long)clock_pair, 1);
+		if (ret) {
+			__free_page(p);
+			clock_pair = NULL;
+			goto nofree;
+		}
+	} else {
+		clock_pair = &clock_pair_glbl;
+	}
+
+	clock_pair_gpa = slow_virt_to_phys(clock_pair);
+	if (!pvclock_get_pvti_cpu0_va()) {
+		ret = -ENODEV;
+		goto err;
+	}
+
+	ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
+			     KVM_CLOCK_PAIRING_WALLCLOCK);
+	if (ret == -KVM_ENOSYS) {
+		ret = -ENODEV;
+		goto err;
+	}
+
+	return ret;
+
+err:
+	kvm_arch_ptp_exit();
+nofree:
+	return ret;
+}
+
+void kvm_arch_ptp_exit(void)
+{
+	if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
+		WARN_ON(set_memory_encrypted((unsigned long)clock_pair, 1));
+		free_page((unsigned long)clock_pair);
+		clock_pair = NULL;
+	}
+}
+
+int kvm_arch_ptp_get_clock(struct timespec64 *ts)
+{
+	long ret;
+
+	ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
+			     clock_pair_gpa,
+			     KVM_CLOCK_PAIRING_WALLCLOCK);
+	if (ret != 0) {
+		pr_err_ratelimited("clock offset hypercall ret %lu\n", ret);
+		return -EOPNOTSUPP;
+	}
+
+	ts->tv_sec = clock_pair->sec;
+	ts->tv_nsec = clock_pair->nsec;
+
+	return 0;
+}
+
+int kvm_arch_ptp_get_crosststamp(u64 *cycle, struct timespec64 *tspec,
+			      struct clocksource **cs)
+{
+	struct pvclock_vcpu_time_info *src;
+	unsigned int version;
+	long ret;
+
+	src = this_cpu_pvti();
+
+	do {
+		/*
+		 * We are using a TSC value read in the hosts
+		 * kvm_hc_clock_pairing handling.
+		 * So any changes to tsc_to_system_mul
+		 * and tsc_shift or any other pvclock
+		 * data invalidate that measurement.
+		 */
+		version = pvclock_read_begin(src);
+
+		ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING,
+				     clock_pair_gpa,
+				     KVM_CLOCK_PAIRING_WALLCLOCK);
+		if (ret != 0) {
+			pr_err_ratelimited("clock pairing hypercall ret %lu\n", ret);
+			return -EOPNOTSUPP;
+		}
+		tspec->tv_sec = clock_pair->sec;
+		tspec->tv_nsec = clock_pair->nsec;
+		*cycle = __pvclock_read_cycles(src, clock_pair->tsc);
+	} while (pvclock_read_retry(src, version));
+
+	*cs = &kvm_clock;
+
+	return 0;
+}