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/hwmon/occ/sysfs.c | 257 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 257 insertions(+) create mode 100644 drivers/hwmon/occ/sysfs.c (limited to 'drivers/hwmon/occ/sysfs.c') diff --git a/drivers/hwmon/occ/sysfs.c b/drivers/hwmon/occ/sysfs.c new file mode 100644 index 000000000..2317301fc --- /dev/null +++ b/drivers/hwmon/occ/sysfs.c @@ -0,0 +1,257 @@ +// SPDX-License-Identifier: GPL-2.0+ +// Copyright IBM Corp 2019 + +#include +#include +#include +#include +#include +#include +#include + +#include "common.h" + +/* OCC status register */ +#define OCC_STAT_MASTER BIT(7) + +/* OCC extended status register */ +#define OCC_EXT_STAT_DVFS_OT BIT(7) +#define OCC_EXT_STAT_DVFS_POWER BIT(6) +#define OCC_EXT_STAT_MEM_THROTTLE BIT(5) +#define OCC_EXT_STAT_QUICK_DROP BIT(4) +#define OCC_EXT_STAT_DVFS_VDD BIT(3) +#define OCC_EXT_STAT_GPU_THROTTLE GENMASK(2, 0) + +static ssize_t occ_active_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + int rc; + bool active; + struct occ *occ = dev_get_drvdata(dev); + + rc = kstrtobool(buf, &active); + if (rc) + return rc; + + rc = occ_active(occ, active); + if (rc) + return rc; + + return count; +} + +static ssize_t occ_sysfs_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int rc; + int val = 0; + struct occ *occ = dev_get_drvdata(dev); + struct occ_poll_response_header *header; + struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr); + + if (occ->active) { + rc = occ_update_response(occ); + if (rc) + return rc; + + header = (struct occ_poll_response_header *)occ->resp.data; + + switch (sattr->index) { + case 0: + val = !!(header->status & OCC_STAT_MASTER); + break; + case 1: + val = 1; + break; + case 2: + val = !!(header->ext_status & OCC_EXT_STAT_DVFS_OT); + break; + case 3: + val = !!(header->ext_status & OCC_EXT_STAT_DVFS_POWER); + break; + case 4: + val = !!(header->ext_status & + OCC_EXT_STAT_MEM_THROTTLE); + break; + case 5: + val = !!(header->ext_status & OCC_EXT_STAT_QUICK_DROP); + break; + case 6: + val = header->occ_state; + break; + case 7: + if (header->status & OCC_STAT_MASTER) + val = hweight8(header->occs_present); + else + val = 1; + break; + case 8: + val = header->ips_status; + break; + case 9: + val = header->mode; + break; + case 10: + val = !!(header->ext_status & OCC_EXT_STAT_DVFS_VDD); + break; + case 11: + val = header->ext_status & OCC_EXT_STAT_GPU_THROTTLE; + break; + default: + return -EINVAL; + } + } else { + if (sattr->index == 1) + val = 0; + else if (sattr->index <= 11) + val = -ENODATA; + else + return -EINVAL; + } + + return sysfs_emit(buf, "%d\n", val); +} + +static ssize_t occ_error_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct occ *occ = dev_get_drvdata(dev); + + occ_update_response(occ); + + return sysfs_emit(buf, "%d\n", occ->error); +} + +static SENSOR_DEVICE_ATTR(occ_master, 0444, occ_sysfs_show, NULL, 0); +static SENSOR_DEVICE_ATTR(occ_active, 0644, occ_sysfs_show, occ_active_store, + 1); +static SENSOR_DEVICE_ATTR(occ_dvfs_overtemp, 0444, occ_sysfs_show, NULL, 2); +static SENSOR_DEVICE_ATTR(occ_dvfs_power, 0444, occ_sysfs_show, NULL, 3); +static SENSOR_DEVICE_ATTR(occ_mem_throttle, 0444, occ_sysfs_show, NULL, 4); +static SENSOR_DEVICE_ATTR(occ_quick_pwr_drop, 0444, occ_sysfs_show, NULL, 5); +static SENSOR_DEVICE_ATTR(occ_state, 0444, occ_sysfs_show, NULL, 6); +static SENSOR_DEVICE_ATTR(occs_present, 0444, occ_sysfs_show, NULL, 7); +static SENSOR_DEVICE_ATTR(occ_ips_status, 0444, occ_sysfs_show, NULL, 8); +static SENSOR_DEVICE_ATTR(occ_mode, 0444, occ_sysfs_show, NULL, 9); +static SENSOR_DEVICE_ATTR(occ_dvfs_vdd, 0444, occ_sysfs_show, NULL, 10); +static SENSOR_DEVICE_ATTR(occ_gpu_throttle, 0444, occ_sysfs_show, NULL, 11); +static DEVICE_ATTR_RO(occ_error); + +static struct attribute *occ_attributes[] = { + &sensor_dev_attr_occ_master.dev_attr.attr, + &sensor_dev_attr_occ_active.dev_attr.attr, + &sensor_dev_attr_occ_dvfs_overtemp.dev_attr.attr, + &sensor_dev_attr_occ_dvfs_power.dev_attr.attr, + &sensor_dev_attr_occ_mem_throttle.dev_attr.attr, + &sensor_dev_attr_occ_quick_pwr_drop.dev_attr.attr, + &sensor_dev_attr_occ_state.dev_attr.attr, + &sensor_dev_attr_occs_present.dev_attr.attr, + &sensor_dev_attr_occ_ips_status.dev_attr.attr, + &sensor_dev_attr_occ_mode.dev_attr.attr, + &sensor_dev_attr_occ_dvfs_vdd.dev_attr.attr, + &sensor_dev_attr_occ_gpu_throttle.dev_attr.attr, + &dev_attr_occ_error.attr, + NULL +}; + +static const struct attribute_group occ_sysfs = { + .attrs = occ_attributes, +}; + +void occ_sysfs_poll_done(struct occ *occ) +{ + const char *name; + struct occ_poll_response_header *header = + (struct occ_poll_response_header *)occ->resp.data; + + /* + * On the first poll response, we haven't yet created the sysfs + * attributes, so don't make any notify calls. + */ + if (!occ->active) + goto done; + + if ((header->status & OCC_STAT_MASTER) != + (occ->prev_stat & OCC_STAT_MASTER)) { + name = sensor_dev_attr_occ_master.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if ((header->ext_status & OCC_EXT_STAT_DVFS_OT) != + (occ->prev_ext_stat & OCC_EXT_STAT_DVFS_OT)) { + name = sensor_dev_attr_occ_dvfs_overtemp.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if ((header->ext_status & OCC_EXT_STAT_DVFS_POWER) != + (occ->prev_ext_stat & OCC_EXT_STAT_DVFS_POWER)) { + name = sensor_dev_attr_occ_dvfs_power.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if ((header->ext_status & OCC_EXT_STAT_MEM_THROTTLE) != + (occ->prev_ext_stat & OCC_EXT_STAT_MEM_THROTTLE)) { + name = sensor_dev_attr_occ_mem_throttle.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if ((header->ext_status & OCC_EXT_STAT_QUICK_DROP) != + (occ->prev_ext_stat & OCC_EXT_STAT_QUICK_DROP)) { + name = sensor_dev_attr_occ_quick_pwr_drop.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if ((header->ext_status & OCC_EXT_STAT_DVFS_VDD) != + (occ->prev_ext_stat & OCC_EXT_STAT_DVFS_VDD)) { + name = sensor_dev_attr_occ_dvfs_vdd.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if ((header->ext_status & OCC_EXT_STAT_GPU_THROTTLE) != + (occ->prev_ext_stat & OCC_EXT_STAT_GPU_THROTTLE)) { + name = sensor_dev_attr_occ_gpu_throttle.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if ((header->status & OCC_STAT_MASTER) && + header->occs_present != occ->prev_occs_present) { + name = sensor_dev_attr_occs_present.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if (header->ips_status != occ->prev_ips_status) { + name = sensor_dev_attr_occ_ips_status.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if (header->mode != occ->prev_mode) { + name = sensor_dev_attr_occ_mode.dev_attr.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + if (occ->error && occ->error != occ->prev_error) { + name = dev_attr_occ_error.attr.name; + sysfs_notify(&occ->bus_dev->kobj, NULL, name); + } + + /* no notifications for OCC state; doesn't indicate error condition */ + +done: + occ->prev_error = occ->error; + occ->prev_stat = header->status; + occ->prev_ext_stat = header->ext_status; + occ->prev_occs_present = header->occs_present; + occ->prev_ips_status = header->ips_status; + occ->prev_mode = header->mode; +} + +int occ_setup_sysfs(struct occ *occ) +{ + return sysfs_create_group(&occ->bus_dev->kobj, &occ_sysfs); +} + +void occ_shutdown_sysfs(struct occ *occ) +{ + sysfs_remove_group(&occ->bus_dev->kobj, &occ_sysfs); +} -- cgit v1.3.1