From 93de2a6a4b91b72607136dd656edf03fb399d27f Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 23 Sep 2026 09:37:21 -0700 Subject: KVM: SEV: Do cache maintenance on the source VM during intra-host migration Manually perform cache maintenance on the source VM during intra-host migration to ensure no stale data is left in CPU caches after the VM is destroyed. Because the source VM is "converted" to a non-SEV VM, KVM's memory reclaim flows won't trigger cache maintenance, e.g. when all guest memory is reclaimed in response to detaching from the mmu_notifier. Note, relying on the destination VM to do cache maintenance isn't an option as KVM doesn't require identical guest memory configurations, i.e. the source VM may have access to memory that the destination VM does not. Enforcing equivalent memory configurations is infeasible, as it would require a *deep* comparison of memslots, e.g. to verify that not only are the memslot identical, but what the memslots point at is also identical. Fixes: b56639318bb2 ("KVM: SEV: Add support for SEV intra host migration") Cc: stable@vger.kernel.org Reported-by: Stefan Teodorescu Signed-off-by: Sean Christopherson Message-ID: <20260923163721.1584779-3-seanjc@google.com> Signed-off-by: Paolo Bonzini --- drivers/macintosh/windfarm_pid.c | 148 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 148 insertions(+) create mode 100644 drivers/macintosh/windfarm_pid.c (limited to 'drivers/macintosh/windfarm_pid.c') diff --git a/drivers/macintosh/windfarm_pid.c b/drivers/macintosh/windfarm_pid.c new file mode 100644 index 000000000..bb31b0e93 --- /dev/null +++ b/drivers/macintosh/windfarm_pid.c @@ -0,0 +1,148 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Windfarm PowerMac thermal control. Generic PID helpers + * + * (c) Copyright 2005 Benjamin Herrenschmidt, IBM Corp. + * + */ + +#include +#include +#include +#include +#include + +#include "windfarm_pid.h" + +#undef DEBUG + +#ifdef DEBUG +#define DBG(args...) printk(args) +#else +#define DBG(args...) do { } while(0) +#endif + +void wf_pid_init(struct wf_pid_state *st, struct wf_pid_param *param) +{ + memset(st, 0, sizeof(struct wf_pid_state)); + st->param = *param; + st->first = 1; +} +EXPORT_SYMBOL_GPL(wf_pid_init); + +s32 wf_pid_run(struct wf_pid_state *st, s32 new_sample) +{ + s64 error, integ, deriv; + s32 target; + int i, hlen = st->param.history_len; + + /* Calculate error term */ + error = new_sample - st->param.itarget; + + /* Get samples into our history buffer */ + if (st->first) { + for (i = 0; i < hlen; i++) { + st->samples[i] = new_sample; + st->errors[i] = error; + } + st->first = 0; + st->index = 0; + } else { + st->index = (st->index + 1) % hlen; + st->samples[st->index] = new_sample; + st->errors[st->index] = error; + } + + /* Calculate integral term */ + for (i = 0, integ = 0; i < hlen; i++) + integ += st->errors[(st->index + hlen - i) % hlen]; + integ *= st->param.interval; + + /* Calculate derivative term */ + deriv = st->errors[st->index] - + st->errors[(st->index + hlen - 1) % hlen]; + deriv /= st->param.interval; + + /* Calculate target */ + target = (s32)((integ * (s64)st->param.gr + deriv * (s64)st->param.gd + + error * (s64)st->param.gp) >> 36); + if (st->param.additive) + target += st->target; + target = max(target, st->param.min); + target = min(target, st->param.max); + st->target = target; + + return st->target; +} +EXPORT_SYMBOL_GPL(wf_pid_run); + +void wf_cpu_pid_init(struct wf_cpu_pid_state *st, + struct wf_cpu_pid_param *param) +{ + memset(st, 0, sizeof(struct wf_cpu_pid_state)); + st->param = *param; + st->first = 1; +} +EXPORT_SYMBOL_GPL(wf_cpu_pid_init); + +s32 wf_cpu_pid_run(struct wf_cpu_pid_state *st, s32 new_power, s32 new_temp) +{ + s64 integ, deriv, prop; + s32 error, target, sval, adj; + int i, hlen = st->param.history_len; + + /* Calculate error term */ + error = st->param.pmaxadj - new_power; + + /* Get samples into our history buffer */ + if (st->first) { + for (i = 0; i < hlen; i++) { + st->powers[i] = new_power; + st->errors[i] = error; + } + st->temps[0] = st->temps[1] = new_temp; + st->first = 0; + st->index = st->tindex = 0; + } else { + st->index = (st->index + 1) % hlen; + st->powers[st->index] = new_power; + st->errors[st->index] = error; + st->tindex = (st->tindex + 1) % 2; + st->temps[st->tindex] = new_temp; + } + + /* Calculate integral term */ + for (i = 0, integ = 0; i < hlen; i++) + integ += st->errors[(st->index + hlen - i) % hlen]; + integ *= st->param.interval; + integ *= st->param.gr; + sval = st->param.tmax - (s32)(integ >> 20); + adj = min(st->param.ttarget, sval); + + DBG("integ: %lx, sval: %lx, adj: %lx\n", integ, sval, adj); + + /* Calculate derivative term */ + deriv = st->temps[st->tindex] - + st->temps[(st->tindex + 2 - 1) % 2]; + deriv /= st->param.interval; + deriv *= st->param.gd; + + /* Calculate proportional term */ + prop = st->last_delta = (new_temp - adj); + prop *= st->param.gp; + + DBG("deriv: %lx, prop: %lx\n", deriv, prop); + + /* Calculate target */ + target = st->target + (s32)((deriv + prop) >> 36); + target = max(target, st->param.min); + target = min(target, st->param.max); + st->target = target; + + return st->target; +} +EXPORT_SYMBOL_GPL(wf_cpu_pid_run); + +MODULE_AUTHOR("Benjamin Herrenschmidt "); +MODULE_DESCRIPTION("PID algorithm for PowerMacs thermal control"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1