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/reset/reset-hsdk.c | 135 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 135 insertions(+) create mode 100644 drivers/reset/reset-hsdk.c (limited to 'drivers/reset/reset-hsdk.c') diff --git a/drivers/reset/reset-hsdk.c b/drivers/reset/reset-hsdk.c new file mode 100644 index 000000000..98460e087 --- /dev/null +++ b/drivers/reset/reset-hsdk.c @@ -0,0 +1,135 @@ +/* + * Copyright (C) 2017 Synopsys. + * + * Synopsys HSDK Development platform reset driver. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define to_hsdk_rst(p) container_of((p), struct hsdk_rst, rcdev) + +struct hsdk_rst { + void __iomem *regs_ctl; + void __iomem *regs_rst; + spinlock_t lock; + struct reset_controller_dev rcdev; +}; + +static const u32 rst_map[] = { + BIT(16), /* APB_RST */ + BIT(17), /* AXI_RST */ + BIT(18), /* ETH_RST */ + BIT(19), /* USB_RST */ + BIT(20), /* SDIO_RST */ + BIT(21), /* HDMI_RST */ + BIT(22), /* GFX_RST */ + BIT(25), /* DMAC_RST */ + BIT(31), /* EBI_RST */ +}; + +#define HSDK_MAX_RESETS ARRAY_SIZE(rst_map) + +#define CGU_SYS_RST_CTRL 0x0 +#define CGU_IP_SW_RESET 0x0 +#define CGU_IP_SW_RESET_DELAY_SHIFT 16 +#define CGU_IP_SW_RESET_DELAY_MASK GENMASK(31, CGU_IP_SW_RESET_DELAY_SHIFT) +#define CGU_IP_SW_RESET_DELAY 0 +#define CGU_IP_SW_RESET_RESET BIT(0) +#define SW_RESET_TIMEOUT 10000 + +static void hsdk_reset_config(struct hsdk_rst *rst, unsigned long id) +{ + writel(rst_map[id], rst->regs_ctl + CGU_SYS_RST_CTRL); +} + +static int hsdk_reset_do(struct hsdk_rst *rst) +{ + u32 reg; + + reg = readl(rst->regs_rst + CGU_IP_SW_RESET); + reg &= ~CGU_IP_SW_RESET_DELAY_MASK; + reg |= CGU_IP_SW_RESET_DELAY << CGU_IP_SW_RESET_DELAY_SHIFT; + reg |= CGU_IP_SW_RESET_RESET; + writel(reg, rst->regs_rst + CGU_IP_SW_RESET); + + /* wait till reset bit is back to 0 */ + return readl_poll_timeout_atomic(rst->regs_rst + CGU_IP_SW_RESET, reg, + !(reg & CGU_IP_SW_RESET_RESET), 5, SW_RESET_TIMEOUT); +} + +static int hsdk_reset_reset(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct hsdk_rst *rst = to_hsdk_rst(rcdev); + unsigned long flags; + int ret; + + spin_lock_irqsave(&rst->lock, flags); + hsdk_reset_config(rst, id); + ret = hsdk_reset_do(rst); + spin_unlock_irqrestore(&rst->lock, flags); + + return ret; +} + +static const struct reset_control_ops hsdk_reset_ops = { + .reset = hsdk_reset_reset, + .deassert = hsdk_reset_reset, +}; + +static int hsdk_reset_probe(struct platform_device *pdev) +{ + struct hsdk_rst *rst; + + rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL); + if (!rst) + return -ENOMEM; + + rst->regs_ctl = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(rst->regs_ctl)) + return PTR_ERR(rst->regs_ctl); + + rst->regs_rst = devm_platform_ioremap_resource(pdev, 1); + if (IS_ERR(rst->regs_rst)) + return PTR_ERR(rst->regs_rst); + + spin_lock_init(&rst->lock); + + rst->rcdev.owner = THIS_MODULE; + rst->rcdev.ops = &hsdk_reset_ops; + rst->rcdev.of_node = pdev->dev.of_node; + rst->rcdev.nr_resets = HSDK_MAX_RESETS; + rst->rcdev.of_reset_n_cells = 1; + + return reset_controller_register(&rst->rcdev); +} + +static const struct of_device_id hsdk_reset_dt_match[] = { + { .compatible = "snps,hsdk-reset" }, + { }, +}; + +static struct platform_driver hsdk_reset_driver = { + .probe = hsdk_reset_probe, + .driver = { + .name = "hsdk-reset", + .of_match_table = hsdk_reset_dt_match, + }, +}; +builtin_platform_driver(hsdk_reset_driver); + +MODULE_AUTHOR("Eugeniy Paltsev "); +MODULE_DESCRIPTION("Synopsys HSDK SDP reset driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1