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/clk/qcom/reset.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 drivers/clk/qcom/reset.c (limited to 'drivers/clk/qcom/reset.c') diff --git a/drivers/clk/qcom/reset.c b/drivers/clk/qcom/reset.c new file mode 100644 index 000000000..d96c96a90 --- /dev/null +++ b/drivers/clk/qcom/reset.c @@ -0,0 +1,59 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2013, The Linux Foundation. All rights reserved. + */ + +#include +#include +#include +#include +#include + +#include "reset.h" + +static int qcom_reset(struct reset_controller_dev *rcdev, unsigned long id) +{ + struct qcom_reset_controller *rst = to_qcom_reset_controller(rcdev); + + rcdev->ops->assert(rcdev, id); + fsleep(rst->reset_map[id].udelay ?: 1); /* use 1 us as default */ + + rcdev->ops->deassert(rcdev, id); + return 0; +} + +static int qcom_reset_set_assert(struct reset_controller_dev *rcdev, + unsigned long id, bool assert) +{ + struct qcom_reset_controller *rst; + const struct qcom_reset_map *map; + u32 mask; + + rst = to_qcom_reset_controller(rcdev); + map = &rst->reset_map[id]; + mask = map->bitmask ? map->bitmask : BIT(map->bit); + + regmap_update_bits(rst->regmap, map->reg, mask, assert ? mask : 0); + + /* Read back the register to ensure write completion, ignore the value */ + regmap_read(rst->regmap, map->reg, &mask); + + return 0; +} + +static int qcom_reset_assert(struct reset_controller_dev *rcdev, unsigned long id) +{ + return qcom_reset_set_assert(rcdev, id, true); +} + +static int qcom_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id) +{ + return qcom_reset_set_assert(rcdev, id, false); +} + +const struct reset_control_ops qcom_reset_ops = { + .reset = qcom_reset, + .assert = qcom_reset_assert, + .deassert = qcom_reset_deassert, +}; +EXPORT_SYMBOL_GPL(qcom_reset_ops); -- cgit v1.3.1