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/powerpc/boot/string.S | 252 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 252 insertions(+) create mode 100644 arch/powerpc/boot/string.S (limited to 'arch/powerpc/boot/string.S') diff --git a/arch/powerpc/boot/string.S b/arch/powerpc/boot/string.S new file mode 100644 index 000000000..76801eb6d --- /dev/null +++ b/arch/powerpc/boot/string.S @@ -0,0 +1,252 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright (C) Paul Mackerras 1997. + * + * NOTE: this code runs in 32 bit mode and is packaged as ELF32. + */ + +#include "ppc_asm.h" + + .text + .globl strcpy +strcpy: + addi r5,r3,-1 + addi r4,r4,-1 +1: lbzu r0,1(r4) + cmpwi 0,r0,0 + stbu r0,1(r5) + bne 1b + blr + + .globl strcat +strcat: + addi r5,r3,-1 + addi r4,r4,-1 +1: lbzu r0,1(r5) + cmpwi 0,r0,0 + bne 1b + addi r5,r5,-1 +1: lbzu r0,1(r4) + cmpwi 0,r0,0 + stbu r0,1(r5) + bne 1b + blr + + .globl strchr +strchr: + addi r3,r3,-1 +1: lbzu r0,1(r3) + cmpw 0,r0,r4 + beqlr + cmpwi 0,r0,0 + bne 1b + li r3,0 + blr + + .globl strcmp +strcmp: + addi r5,r3,-1 + addi r4,r4,-1 +1: lbzu r3,1(r5) + cmpwi 1,r3,0 + lbzu r0,1(r4) + subf. r3,r0,r3 + beqlr 1 + beq 1b + blr + + .globl strncmp +strncmp: + mtctr r5 + addi r5,r3,-1 + addi r4,r4,-1 +1: lbzu r3,1(r5) + cmpwi 1,r3,0 + lbzu r0,1(r4) + subf. r3,r0,r3 + beqlr 1 + bdnzt eq,1b + blr + + .globl strlen +strlen: + addi r4,r3,-1 +1: lbzu r0,1(r4) + cmpwi 0,r0,0 + bne 1b + subf r3,r3,r4 + blr + + .globl memset +memset: + rlwimi r4,r4,8,16,23 + rlwimi r4,r4,16,0,15 + addi r6,r3,-4 + cmplwi 0,r5,4 + blt 7f + stwu r4,4(r6) + beqlr + andi. r0,r6,3 + add r5,r0,r5 + subf r6,r0,r6 + rlwinm r0,r5,32-2,2,31 + mtctr r0 + bdz 6f +1: stwu r4,4(r6) + bdnz 1b +6: andi. r5,r5,3 +7: cmpwi 0,r5,0 + beqlr + mtctr r5 + addi r6,r6,3 +8: stbu r4,1(r6) + bdnz 8b + blr + + .globl memmove +memmove: + cmplw 0,r3,r4 + bgt backwards_memcpy + /* fall through */ + + .globl memcpy +memcpy: + rlwinm. r7,r5,32-3,3,31 /* r7 = r5 >> 3 */ + addi r6,r3,-4 + addi r4,r4,-4 + beq 3f /* if less than 8 bytes to do */ + andi. r0,r6,3 /* get dest word aligned */ + mtctr r7 + bne 5f + andi. r0,r4,3 /* check src word aligned too */ + bne 3f +1: lwz r7,4(r4) + lwzu r8,8(r4) + stw r7,4(r6) + stwu r8,8(r6) + bdnz 1b + andi. r5,r5,7 +2: cmplwi 0,r5,4 + blt 3f + lwzu r0,4(r4) + addi r5,r5,-4 + stwu r0,4(r6) +3: cmpwi 0,r5,0 + beqlr + mtctr r5 + addi r4,r4,3 + addi r6,r6,3 +4: lbzu r0,1(r4) + stbu r0,1(r6) + bdnz 4b + blr +5: subfic r0,r0,4 + cmpw cr1,r0,r5 + add r7,r0,r4 + andi. r7,r7,3 /* will source be word-aligned too? */ + ble cr1,3b + bne 3b /* do byte-by-byte if not */ + mtctr r0 +6: lbz r7,4(r4) + addi r4,r4,1 + stb r7,4(r6) + addi r6,r6,1 + bdnz 6b + subf r5,r0,r5 + rlwinm. r7,r5,32-3,3,31 + beq 2b + mtctr r7 + b 1b + + .globl backwards_memcpy +backwards_memcpy: + rlwinm. r7,r5,32-3,3,31 /* r7 = r5 >> 3 */ + add r6,r3,r5 + add r4,r4,r5 + beq 3f + andi. r0,r6,3 + mtctr r7 + bne 5f + andi. r0,r4,3 + bne 3f +1: lwz r7,-4(r4) + lwzu r8,-8(r4) + stw r7,-4(r6) + stwu r8,-8(r6) + bdnz 1b + andi. r5,r5,7 +2: cmplwi 0,r5,4 + blt 3f + lwzu r0,-4(r4) + subi r5,r5,4 + stwu r0,-4(r6) +3: cmpwi 0,r5,0 + beqlr + mtctr r5 +4: lbzu r0,-1(r4) + stbu r0,-1(r6) + bdnz 4b + blr +5: cmpw cr1,r0,r5 + subf r7,r0,r4 + andi. r7,r7,3 + ble cr1,3b + bne 3b + mtctr r0 +6: lbzu r7,-1(r4) + stbu r7,-1(r6) + bdnz 6b + subf r5,r0,r5 + rlwinm. r7,r5,32-3,3,31 + beq 2b + mtctr r7 + b 1b + + .globl memchr +memchr: + cmpwi 0,r5,0 + blelr + mtctr r5 + addi r3,r3,-1 +1: lbzu r0,1(r3) + cmpw r0,r4 + beqlr + bdnz 1b + li r3,0 + blr + + .globl memcmp +memcmp: + cmpwi 0,r5,0 + ble 2f + mtctr r5 + addi r6,r3,-1 + addi r4,r4,-1 +1: lbzu r3,1(r6) + lbzu r0,1(r4) + subf. r3,r0,r3 + bdnzt 2,1b + blr +2: li r3,0 + blr + + +/* + * Flush the dcache and invalidate the icache for a range of addresses. + * + * flush_cache(addr, len) + */ + .global flush_cache +flush_cache: + addi 4,4,0x1f /* len = (len + 0x1f) / 0x20 */ + rlwinm. 4,4,27,5,31 + mtctr 4 + beqlr +1: dcbf 0,3 + icbi 0,3 + addi 3,3,0x20 + bdnz 1b + sync + isync + blr + -- cgit v1.3.1