linux/drivers/ptp/ptp_kvm_x86.c
Kele Huang c2402d43d1 ptp: fix error print of ptp_kvm on X86_64 platform
Commit a86ed2cfa1 ("ptp: Don't print an error if ptp_kvm is not supported")
fixes the error message print on ARM platform by only concerning about
the case that the error returned from kvm_arch_ptp_init() is not -EOPNOTSUPP.
Although the ARM platform returns -EOPNOTSUPP if ptp_kvm is not supported
while X86_64 platform returns -KVM_EOPNOTSUPP, both error codes share the
same value 95.

Actually kvm_arch_ptp_init() on X86_64 platform can return three kinds of
errors (-KVM_ENOSYS, -KVM_EOPNOTSUPP and -KVM_EFAULT). The problem is that
-KVM_EOPNOTSUPP is masked out and -KVM_EFAULT is ignored among them.
This patch fixes this by returning them to ptp_kvm_init() respectively.

Signed-off-by: Kele Huang <huangkele@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-15 11:19:25 +01:00

93 lines
2.0 KiB
C

// 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>
static phys_addr_t clock_pair_gpa;
static struct kvm_clock_pairing clock_pair;
int kvm_arch_ptp_init(void)
{
long ret;
if (!kvm_para_available())
return -ENODEV;
clock_pair_gpa = slow_virt_to_phys(&clock_pair);
if (!pvclock_get_pvti_cpu0_va())
return -ENODEV;
ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa,
KVM_CLOCK_PAIRING_WALLCLOCK);
if (ret == -KVM_ENOSYS)
return -ENODEV;
return ret;
}
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;
}