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// 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 -EOPNOTSUPP;
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 = -EOPNOTSUPP;
goto err;
}
ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
KVM_CLOCK_PAIRING_WALLCLOCK);
if (ret == -KVM_ENOSYS) {
ret = -EOPNOTSUPP;
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,
enum clocksource_ids *cs_id)
{
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_id = CSID_X86_KVM_CLK;
return 0;
}