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/mtd/maps/physmap-gemini.c | 200 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) create mode 100644 drivers/mtd/maps/physmap-gemini.c (limited to 'drivers/mtd/maps/physmap-gemini.c') diff --git a/drivers/mtd/maps/physmap-gemini.c b/drivers/mtd/maps/physmap-gemini.c new file mode 100644 index 000000000..1c34b4ef7 --- /dev/null +++ b/drivers/mtd/maps/physmap-gemini.c @@ -0,0 +1,200 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Cortina Systems Gemini OF physmap add-on + * Copyright (C) 2017 Linus Walleij + * + * This SoC has an elaborate flash control register, so we need to + * detect and set it up when booting on this platform. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "physmap-gemini.h" + +/* + * The Flash-relevant parts of the global status register + * These would also be relevant for a NAND driver. + */ +#define GLOBAL_STATUS 0x04 +#define FLASH_TYPE_MASK (0x3 << 24) +#define FLASH_TYPE_NAND_2K (0x3 << 24) +#define FLASH_TYPE_NAND_512 (0x2 << 24) +#define FLASH_TYPE_PARALLEL (0x1 << 24) +#define FLASH_TYPE_SERIAL (0x0 << 24) +/* if parallel */ +#define FLASH_WIDTH_16BIT (1 << 23) /* else 8 bit */ +/* if serial */ +#define FLASH_ATMEL (1 << 23) /* else STM */ + +#define FLASH_SIZE_MASK (0x3 << 21) +#define NAND_256M (0x3 << 21) /* and more */ +#define NAND_128M (0x2 << 21) +#define NAND_64M (0x1 << 21) +#define NAND_32M (0x0 << 21) +#define ATMEL_16M (0x3 << 21) /* and more */ +#define ATMEL_8M (0x2 << 21) +#define ATMEL_4M_2M (0x1 << 21) +#define ATMEL_1M (0x0 << 21) /* and less */ +#define STM_32M (1 << 22) /* and more */ +#define STM_16M (0 << 22) /* and less */ + +#define FLASH_PARALLEL_HIGH_PIN_CNT (1 << 20) /* else low pin cnt */ + +struct gemini_flash { + struct device *dev; + struct pinctrl *p; + struct pinctrl_state *enabled_state; + struct pinctrl_state *disabled_state; +}; + +/* Static local state */ +static struct gemini_flash *gf; + +static void gemini_flash_enable_pins(void) +{ + int ret; + + if (IS_ERR(gf->enabled_state)) + return; + ret = pinctrl_select_state(gf->p, gf->enabled_state); + if (ret) + dev_err(gf->dev, "failed to enable pins\n"); +} + +static void gemini_flash_disable_pins(void) +{ + int ret; + + if (IS_ERR(gf->disabled_state)) + return; + ret = pinctrl_select_state(gf->p, gf->disabled_state); + if (ret) + dev_err(gf->dev, "failed to disable pins\n"); +} + +static map_word __xipram gemini_flash_map_read(struct map_info *map, + unsigned long ofs) +{ + map_word ret; + + gemini_flash_enable_pins(); + ret = inline_map_read(map, ofs); + gemini_flash_disable_pins(); + + return ret; +} + +static void __xipram gemini_flash_map_write(struct map_info *map, + const map_word datum, + unsigned long ofs) +{ + gemini_flash_enable_pins(); + inline_map_write(map, datum, ofs); + gemini_flash_disable_pins(); +} + +static void __xipram gemini_flash_map_copy_from(struct map_info *map, + void *to, unsigned long from, + ssize_t len) +{ + gemini_flash_enable_pins(); + inline_map_copy_from(map, to, from, len); + gemini_flash_disable_pins(); +} + +static void __xipram gemini_flash_map_copy_to(struct map_info *map, + unsigned long to, + const void *from, ssize_t len) +{ + gemini_flash_enable_pins(); + inline_map_copy_to(map, to, from, len); + gemini_flash_disable_pins(); +} + +int of_flash_probe_gemini(struct platform_device *pdev, + struct device_node *np, + struct map_info *map) +{ + struct regmap *rmap; + struct device *dev = &pdev->dev; + u32 val; + int ret; + + /* Multiplatform guard */ + if (!of_device_is_compatible(np, "cortina,gemini-flash")) + return 0; + + gf = devm_kzalloc(dev, sizeof(*gf), GFP_KERNEL); + if (!gf) + return -ENOMEM; + gf->dev = dev; + + rmap = syscon_regmap_lookup_by_phandle(np, "syscon"); + if (IS_ERR(rmap)) { + dev_err(dev, "no syscon\n"); + return PTR_ERR(rmap); + } + + ret = regmap_read(rmap, GLOBAL_STATUS, &val); + if (ret) { + dev_err(dev, "failed to read global status register\n"); + return -ENODEV; + } + dev_dbg(dev, "global status reg: %08x\n", val); + + /* + * It would be contradictory if a physmap flash was NOT parallel. + */ + if ((val & FLASH_TYPE_MASK) != FLASH_TYPE_PARALLEL) { + dev_err(dev, "flash is not parallel\n"); + return -ENODEV; + } + + /* + * Complain if DT data and hardware definition is different. + */ + if (val & FLASH_WIDTH_16BIT) { + if (map->bankwidth != 2) + dev_warn(dev, "flash hardware say flash is 16 bit wide but DT says it is %d bits wide\n", + map->bankwidth * 8); + } else { + if (map->bankwidth != 1) + dev_warn(dev, "flash hardware say flash is 8 bit wide but DT says it is %d bits wide\n", + map->bankwidth * 8); + } + + gf->p = devm_pinctrl_get(dev); + if (IS_ERR(gf->p)) { + dev_err(dev, "no pinctrl handle\n"); + ret = PTR_ERR(gf->p); + return ret; + } + + gf->enabled_state = pinctrl_lookup_state(gf->p, "enabled"); + if (IS_ERR(gf->enabled_state)) + dev_err(dev, "no enabled pin control state\n"); + + gf->disabled_state = pinctrl_lookup_state(gf->p, "disabled"); + if (IS_ERR(gf->disabled_state)) { + dev_err(dev, "no disabled pin control state\n"); + } else { + ret = pinctrl_select_state(gf->p, gf->disabled_state); + if (ret) + dev_err(gf->dev, "failed to disable pins\n"); + } + + map->read = gemini_flash_map_read; + map->write = gemini_flash_map_write; + map->copy_from = gemini_flash_map_copy_from; + map->copy_to = gemini_flash_map_copy_to; + + dev_info(dev, "initialized Gemini-specific physmap control\n"); + + return 0; +} -- cgit v1.3.1