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6365ba64b4
KVM_HC_CLOCK_PAIRING currently fails inside SEV-SNP guests because the guest passes an address to static data to the host. In confidential computing the host can't access arbitrary guest memory so handling the hypercall runs into an "rmpfault". To make the hypercall work, the guest needs to explicitly mark the memory as decrypted. Do that in kvm_arch_ptp_init(), but retain the previous behavior for non-confidential guests to save us from having to allocate memory. Add a new arch-specific function (kvm_arch_ptp_exit()) to free the allocation and mark the memory as encrypted again. Signed-off-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com> Link: https://lore.kernel.org/r/20230308150531.477741-1-jpiotrowski@linux.microsoft.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
159 lines
3.1 KiB
C
159 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Virtual PTP 1588 clock for use with KVM guests
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*
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* Copyright (C) 2017 Red Hat Inc.
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*/
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/ptp_kvm.h>
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#include <uapi/linux/kvm_para.h>
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#include <asm/kvm_para.h>
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#include <uapi/asm/kvm_para.h>
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#include <linux/ptp_clock_kernel.h>
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struct kvm_ptp_clock {
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struct ptp_clock *ptp_clock;
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struct ptp_clock_info caps;
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};
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static DEFINE_SPINLOCK(kvm_ptp_lock);
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static int ptp_kvm_get_time_fn(ktime_t *device_time,
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struct system_counterval_t *system_counter,
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void *ctx)
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{
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long ret;
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u64 cycle;
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struct timespec64 tspec;
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struct clocksource *cs;
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spin_lock(&kvm_ptp_lock);
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preempt_disable_notrace();
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ret = kvm_arch_ptp_get_crosststamp(&cycle, &tspec, &cs);
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if (ret) {
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spin_unlock(&kvm_ptp_lock);
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preempt_enable_notrace();
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return ret;
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}
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preempt_enable_notrace();
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system_counter->cycles = cycle;
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system_counter->cs = cs;
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*device_time = timespec64_to_ktime(tspec);
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spin_unlock(&kvm_ptp_lock);
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return 0;
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}
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static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
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struct system_device_crosststamp *xtstamp)
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{
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return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL,
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NULL, xtstamp);
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}
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/*
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* PTP clock operations
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*/
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static int ptp_kvm_adjfine(struct ptp_clock_info *ptp, long delta)
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{
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return -EOPNOTSUPP;
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}
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static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
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{
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return -EOPNOTSUPP;
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}
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static int ptp_kvm_settime(struct ptp_clock_info *ptp,
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const struct timespec64 *ts)
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{
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return -EOPNOTSUPP;
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}
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static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
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{
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long ret;
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struct timespec64 tspec;
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spin_lock(&kvm_ptp_lock);
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ret = kvm_arch_ptp_get_clock(&tspec);
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if (ret) {
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spin_unlock(&kvm_ptp_lock);
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return ret;
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}
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spin_unlock(&kvm_ptp_lock);
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memcpy(ts, &tspec, sizeof(struct timespec64));
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return 0;
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}
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static int ptp_kvm_enable(struct ptp_clock_info *ptp,
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struct ptp_clock_request *rq, int on)
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{
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return -EOPNOTSUPP;
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}
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static const struct ptp_clock_info ptp_kvm_caps = {
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.owner = THIS_MODULE,
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.name = "KVM virtual PTP",
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.max_adj = 0,
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.n_ext_ts = 0,
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.n_pins = 0,
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.pps = 0,
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.adjfine = ptp_kvm_adjfine,
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.adjtime = ptp_kvm_adjtime,
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.gettime64 = ptp_kvm_gettime,
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.settime64 = ptp_kvm_settime,
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.enable = ptp_kvm_enable,
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.getcrosststamp = ptp_kvm_getcrosststamp,
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};
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/* module operations */
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static struct kvm_ptp_clock kvm_ptp_clock;
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static void __exit ptp_kvm_exit(void)
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{
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ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
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kvm_arch_ptp_exit();
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}
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static int __init ptp_kvm_init(void)
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{
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long ret;
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ret = kvm_arch_ptp_init();
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if (ret) {
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if (ret != -EOPNOTSUPP)
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pr_err("fail to initialize ptp_kvm");
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return ret;
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}
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kvm_ptp_clock.caps = ptp_kvm_caps;
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kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
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return PTR_ERR_OR_ZERO(kvm_ptp_clock.ptp_clock);
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}
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module_init(ptp_kvm_init);
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module_exit(ptp_kvm_exit);
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MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
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MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
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MODULE_LICENSE("GPL");
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