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/mips/power/Makefile | 2 ++ arch/mips/power/cpu.c | 43 +++++++++++++++++++++++++++++ arch/mips/power/hibernate.c | 12 +++++++++ arch/mips/power/hibernate_asm.S | 60 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 117 insertions(+) create mode 100644 arch/mips/power/Makefile create mode 100644 arch/mips/power/cpu.c create mode 100644 arch/mips/power/hibernate.c create mode 100644 arch/mips/power/hibernate_asm.S (limited to 'arch/mips/power') diff --git a/arch/mips/power/Makefile b/arch/mips/power/Makefile new file mode 100644 index 000000000..14b7d9ee6 --- /dev/null +++ b/arch/mips/power/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +obj-$(CONFIG_HIBERNATION) += cpu.o hibernate.o hibernate_asm.o diff --git a/arch/mips/power/cpu.c b/arch/mips/power/cpu.c new file mode 100644 index 000000000..d8ef7778e --- /dev/null +++ b/arch/mips/power/cpu.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Suspend support specific for mips. + * + * Copyright (C) 2009 Lemote Inc. + * Author: Hu Hongbing + * Wu Zhangjin + */ +#include +#include +#include +#include + +static u32 saved_status; +struct pt_regs saved_regs; + +void save_processor_state(void) +{ + saved_status = read_c0_status(); + + if (is_fpu_owner()) + save_fp(current); + + save_dsp(current); +} + +void restore_processor_state(void) +{ + write_c0_status(saved_status); + + if (is_fpu_owner()) + restore_fp(current); + + restore_dsp(current); +} + +int pfn_is_nosave(unsigned long pfn) +{ + unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin)); + unsigned long nosave_end_pfn = PFN_UP(__pa(&__nosave_end)); + + return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn); +} diff --git a/arch/mips/power/hibernate.c b/arch/mips/power/hibernate.c new file mode 100644 index 000000000..192879e76 --- /dev/null +++ b/arch/mips/power/hibernate.c @@ -0,0 +1,12 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +extern int restore_image(void); + +int swsusp_arch_resume(void) +{ + /* Avoid TLB mismatch during and after kernel resume */ + local_flush_tlb_all(); + return restore_image(); +} diff --git a/arch/mips/power/hibernate_asm.S b/arch/mips/power/hibernate_asm.S new file mode 100644 index 000000000..e62538734 --- /dev/null +++ b/arch/mips/power/hibernate_asm.S @@ -0,0 +1,60 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Hibernation support specific for mips - temporary page tables + * + * Copyright (C) 2009 Lemote Inc. + * Author: Hu Hongbing + * Wu Zhangjin + */ +#include +#include +#include + +.text +LEAF(swsusp_arch_suspend) + PTR_LA t0, saved_regs + PTR_S ra, PT_R31(t0) + PTR_S sp, PT_R29(t0) + PTR_S fp, PT_R30(t0) + PTR_S gp, PT_R28(t0) + PTR_S s0, PT_R16(t0) + PTR_S s1, PT_R17(t0) + PTR_S s2, PT_R18(t0) + PTR_S s3, PT_R19(t0) + PTR_S s4, PT_R20(t0) + PTR_S s5, PT_R21(t0) + PTR_S s6, PT_R22(t0) + PTR_S s7, PT_R23(t0) + j swsusp_save +END(swsusp_arch_suspend) + +LEAF(restore_image) + PTR_L t0, restore_pblist +0: + PTR_L t1, PBE_ADDRESS(t0) /* source */ + PTR_L t2, PBE_ORIG_ADDRESS(t0) /* destination */ + PTR_ADDU t3, t1, _PAGE_SIZE +1: + REG_L t8, (t1) + REG_S t8, (t2) + PTR_ADDIU t1, t1, SZREG + PTR_ADDIU t2, t2, SZREG + bne t1, t3, 1b + PTR_L t0, PBE_NEXT(t0) + bnez t0, 0b + PTR_LA t0, saved_regs + PTR_L ra, PT_R31(t0) + PTR_L sp, PT_R29(t0) + PTR_L fp, PT_R30(t0) + PTR_L gp, PT_R28(t0) + PTR_L s0, PT_R16(t0) + PTR_L s1, PT_R17(t0) + PTR_L s2, PT_R18(t0) + PTR_L s3, PT_R19(t0) + PTR_L s4, PT_R20(t0) + PTR_L s5, PT_R21(t0) + PTR_L s6, PT_R22(t0) + PTR_L s7, PT_R23(t0) + PTR_LI v0, 0x0 + jr ra +END(restore_image) -- cgit v1.3.1