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 --- arch/m68k/mm/cache.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 127 insertions(+) create mode 100644 arch/m68k/mm/cache.c (limited to 'arch/m68k/mm/cache.c') diff --git a/arch/m68k/mm/cache.c b/arch/m68k/mm/cache.c new file mode 100644 index 000000000..dde978e66 --- /dev/null +++ b/arch/m68k/mm/cache.c @@ -0,0 +1,127 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/m68k/mm/cache.c + * + * Instruction cache handling + * + * Copyright (C) 1995 Hamish Macdonald + */ + +#include +#include +#include + + +static unsigned long virt_to_phys_slow(unsigned long vaddr) +{ + if (CPU_IS_060) { + unsigned long paddr; + + /* The PLPAR instruction causes an access error if the translation + * is not possible. To catch this we use the same exception mechanism + * as for user space accesses in . */ + asm volatile (".chip 68060\n" + "1: plpar (%0)\n" + ".chip 68k\n" + "2:\n" + ".section .fixup,\"ax\"\n" + " .even\n" + "3: sub.l %0,%0\n" + " jra 2b\n" + ".previous\n" + ".section __ex_table,\"a\"\n" + " .align 4\n" + " .long 1b,3b\n" + ".previous" + : "=a" (paddr) + : "0" (vaddr)); + return paddr; + } else if (CPU_IS_040) { + unsigned long mmusr; + + asm volatile (".chip 68040\n\t" + "ptestr (%1)\n\t" + "movec %%mmusr, %0\n\t" + ".chip 68k" + : "=r" (mmusr) + : "a" (vaddr)); + + if (mmusr & MMU_R_040) + return (mmusr & PAGE_MASK) | (vaddr & ~PAGE_MASK); + } else { + WARN_ON_ONCE(!CPU_IS_040_OR_060); + } + return 0; +} + +/* Push n pages at kernel virtual address and clear the icache */ +/* RZ: use cpush %bc instead of cpush %dc, cinv %ic */ +void flush_icache_user_range(unsigned long address, unsigned long endaddr) +{ + if (CPU_IS_COLDFIRE) { + unsigned long start, end; + start = address & ICACHE_SET_MASK; + end = endaddr & ICACHE_SET_MASK; + if (start > end) { + flush_cf_icache(0, end); + end = ICACHE_MAX_ADDR; + } + flush_cf_icache(start, end); + } else if (CPU_IS_040_OR_060) { + address &= PAGE_MASK; + + do { + asm volatile ("nop\n\t" + ".chip 68040\n\t" + "cpushp %%bc,(%0)\n\t" + ".chip 68k" + : : "a" (virt_to_phys_slow(address))); + address += PAGE_SIZE; + } while (address < endaddr); + } else { + unsigned long tmp; + asm volatile ("movec %%cacr,%0\n\t" + "orw %1,%0\n\t" + "movec %0,%%cacr" + : "=&d" (tmp) + : "di" (FLUSH_I)); + } +} + +void flush_icache_range(unsigned long address, unsigned long endaddr) +{ + set_fc(SUPER_DATA); + flush_icache_user_range(address, endaddr); + set_fc(USER_DATA); +} +EXPORT_SYMBOL(flush_icache_range); + +void flush_icache_user_page(struct vm_area_struct *vma, struct page *page, + unsigned long addr, int len) +{ + if (CPU_IS_COLDFIRE) { + unsigned long start, end; + start = addr & ICACHE_SET_MASK; + end = (addr + len) & ICACHE_SET_MASK; + if (start > end) { + flush_cf_icache(0, end); + end = ICACHE_MAX_ADDR; + } + flush_cf_icache(start, end); + + } else if (CPU_IS_040_OR_060) { + asm volatile ("nop\n\t" + ".chip 68040\n\t" + "cpushp %%bc,(%0)\n\t" + ".chip 68k" + : : "a" (page_to_phys(page))); + } else { + unsigned long tmp; + asm volatile ("movec %%cacr,%0\n\t" + "orw %1,%0\n\t" + "movec %0,%%cacr" + : "=&d" (tmp) + : "di" (FLUSH_I)); + } +} + -- cgit v1.3.1