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/firmware/trusted_foundations.c | 184 +++++++++++++++++++++++++++++++++ 1 file changed, 184 insertions(+) create mode 100644 drivers/firmware/trusted_foundations.c (limited to 'drivers/firmware/trusted_foundations.c') diff --git a/drivers/firmware/trusted_foundations.c b/drivers/firmware/trusted_foundations.c new file mode 100644 index 000000000..1389fa941 --- /dev/null +++ b/drivers/firmware/trusted_foundations.c @@ -0,0 +1,184 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Trusted Foundations support for ARM CPUs + * + * Copyright (c) 2013, NVIDIA Corporation. + */ + +#include +#include +#include + +#include + +#include +#include +#include + +#define TF_CACHE_MAINT 0xfffff100 + +#define TF_CACHE_ENABLE 1 +#define TF_CACHE_DISABLE 2 +#define TF_CACHE_REENABLE 4 + +#define TF_SET_CPU_BOOT_ADDR_SMC 0xfffff200 + +#define TF_CPU_PM 0xfffffffc +#define TF_CPU_PM_S3 0xffffffe3 +#define TF_CPU_PM_S2 0xffffffe6 +#define TF_CPU_PM_S2_NO_MC_CLK 0xffffffe5 +#define TF_CPU_PM_S1 0xffffffe4 +#define TF_CPU_PM_S1_NOFLUSH_L2 0xffffffe7 + +static unsigned long tf_idle_mode = TF_PM_MODE_NONE; +static unsigned long cpu_boot_addr; + +static void tf_generic_smc(u32 type, u32 arg1, u32 arg2) +{ + register u32 r0 asm("r0") = type; + register u32 r1 asm("r1") = arg1; + register u32 r2 asm("r2") = arg2; + + asm volatile( + ".arch_extension sec\n\t" + "stmfd sp!, {r4 - r11}\n\t" + __asmeq("%0", "r0") + __asmeq("%1", "r1") + __asmeq("%2", "r2") + "mov r3, #0\n\t" + "mov r4, #0\n\t" + "smc #0\n\t" + "ldmfd sp!, {r4 - r11}\n\t" + : + : "r" (r0), "r" (r1), "r" (r2) + : "memory", "r3", "r12", "lr"); +} + +static int tf_set_cpu_boot_addr(int cpu, unsigned long boot_addr) +{ + cpu_boot_addr = boot_addr; + tf_generic_smc(TF_SET_CPU_BOOT_ADDR_SMC, cpu_boot_addr, 0); + + return 0; +} + +static int tf_prepare_idle(unsigned long mode) +{ + switch (mode) { + case TF_PM_MODE_LP0: + tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S3, cpu_boot_addr); + break; + + case TF_PM_MODE_LP1: + tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S2, cpu_boot_addr); + break; + + case TF_PM_MODE_LP1_NO_MC_CLK: + tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S2_NO_MC_CLK, + cpu_boot_addr); + break; + + case TF_PM_MODE_LP2: + tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S1, cpu_boot_addr); + break; + + case TF_PM_MODE_LP2_NOFLUSH_L2: + tf_generic_smc(TF_CPU_PM, TF_CPU_PM_S1_NOFLUSH_L2, + cpu_boot_addr); + break; + + case TF_PM_MODE_NONE: + break; + + default: + return -EINVAL; + } + + tf_idle_mode = mode; + + return 0; +} + +#ifdef CONFIG_CACHE_L2X0 +static void tf_cache_write_sec(unsigned long val, unsigned int reg) +{ + u32 enable_op, l2x0_way_mask = 0xff; + + switch (reg) { + case L2X0_CTRL: + if (l2x0_saved_regs.aux_ctrl & L310_AUX_CTRL_ASSOCIATIVITY_16) + l2x0_way_mask = 0xffff; + + switch (tf_idle_mode) { + case TF_PM_MODE_LP2: + enable_op = TF_CACHE_REENABLE; + break; + + default: + enable_op = TF_CACHE_ENABLE; + break; + } + + if (val == L2X0_CTRL_EN) + tf_generic_smc(TF_CACHE_MAINT, enable_op, + l2x0_saved_regs.aux_ctrl); + else + tf_generic_smc(TF_CACHE_MAINT, TF_CACHE_DISABLE, + l2x0_way_mask); + break; + + default: + break; + } +} + +static int tf_init_cache(void) +{ + outer_cache.write_sec = tf_cache_write_sec; + + return 0; +} +#endif /* CONFIG_CACHE_L2X0 */ + +static const struct firmware_ops trusted_foundations_ops = { + .set_cpu_boot_addr = tf_set_cpu_boot_addr, + .prepare_idle = tf_prepare_idle, +#ifdef CONFIG_CACHE_L2X0 + .l2x0_init = tf_init_cache, +#endif +}; + +void register_trusted_foundations(struct trusted_foundations_platform_data *pd) +{ + /* + * we are not using version information for now since currently + * supported SMCs are compatible with all TF releases + */ + register_firmware_ops(&trusted_foundations_ops); +} + +void of_register_trusted_foundations(void) +{ + struct device_node *node; + struct trusted_foundations_platform_data pdata; + int err; + + node = of_find_compatible_node(NULL, NULL, "tlm,trusted-foundations"); + if (!node) + return; + + err = of_property_read_u32(node, "tlm,version-major", + &pdata.version_major); + if (err != 0) + panic("Trusted Foundation: missing version-major property\n"); + err = of_property_read_u32(node, "tlm,version-minor", + &pdata.version_minor); + if (err != 0) + panic("Trusted Foundation: missing version-minor property\n"); + register_trusted_foundations(&pdata); +} + +bool trusted_foundations_registered(void) +{ + return firmware_ops == &trusted_foundations_ops; +} -- cgit v1.3.1