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| author | Sean Christopherson <seanjc@google.com> | 2026-09-23 09:37:21 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2026-09-26 00:39:55 -0400 |
| commit | 93de2a6a4b91b72607136dd656edf03fb399d27f (patch) | |
| tree | 9220c76eb23cb39a146fac9692ee69afa4aa3135 /arch/alpha/boot/head.S | |
| download | linux-stable-93de2a6a4b91b72607136dd656edf03fb399d27f.tar.gz linux-stable-93de2a6a4b91b72607136dd656edf03fb399d27f.zip | |
KVM: SEV: Do cache maintenance on the source VM during intra-host migrationgrafted
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 <fane@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260923163721.1584779-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/alpha/boot/head.S')
| -rw-r--r-- | arch/alpha/boot/head.S | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/alpha/boot/head.S b/arch/alpha/boot/head.S new file mode 100644 index 000000000..06a7c95fe --- /dev/null +++ b/arch/alpha/boot/head.S @@ -0,0 +1,124 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * arch/alpha/boot/head.S + * + * initial bootloader stuff.. + */ + +#include <asm/pal.h> + + .set noreorder + .globl __start + .ent __start +__start: + br $29,2f +2: ldgp $29,0($29) + jsr $26,start_kernel + call_pal PAL_halt + .end __start + + .align 5 + .globl wrent + .ent wrent +wrent: + .prologue 0 + call_pal PAL_wrent + ret ($26) + .end wrent + + .align 5 + .globl wrkgp + .ent wrkgp +wrkgp: + .prologue 0 + call_pal PAL_wrkgp + ret ($26) + .end wrkgp + + .align 5 + .globl switch_to_osf_pal + .ent switch_to_osf_pal +switch_to_osf_pal: + subq $30,128,$30 + .frame $30,128,$26 + stq $26,0($30) + stq $1,8($30) + stq $2,16($30) + stq $3,24($30) + stq $4,32($30) + stq $5,40($30) + stq $6,48($30) + stq $7,56($30) + stq $8,64($30) + stq $9,72($30) + stq $10,80($30) + stq $11,88($30) + stq $12,96($30) + stq $13,104($30) + stq $14,112($30) + stq $15,120($30) + .prologue 0 + + stq $30,0($17) /* save KSP in PCB */ + + bis $30,$30,$20 /* a4 = KSP */ + br $17,1f + + ldq $26,0($30) + ldq $1,8($30) + ldq $2,16($30) + ldq $3,24($30) + ldq $4,32($30) + ldq $5,40($30) + ldq $6,48($30) + ldq $7,56($30) + ldq $8,64($30) + ldq $9,72($30) + ldq $10,80($30) + ldq $11,88($30) + ldq $12,96($30) + ldq $13,104($30) + ldq $14,112($30) + ldq $15,120($30) + addq $30,128,$30 + ret ($26) +1: call_pal PAL_swppal + .end switch_to_osf_pal + + .align 3 + .globl tbi + .ent tbi +tbi: + .prologue 0 + call_pal PAL_tbi + ret ($26) + .end tbi + + .align 3 + .globl halt + .ent halt +halt: + .prologue 0 + call_pal PAL_halt + .end halt + +/* $16 - new stack page */ + .align 3 + .globl move_stack + .ent move_stack +move_stack: + .prologue 0 + lda $0, 0x1fff($31) + and $0, $30, $1 /* Stack offset */ + or $1, $16, $16 /* New stack pointer */ + mov $30, $1 + mov $16, $2 +1: ldq $3, 0($1) /* Move the stack */ + addq $1, 8, $1 + stq $3, 0($2) + and $0, $1, $4 + addq $2, 8, $2 + bne $4, 1b + mov $16, $30 + ret ($26) + .end move_stack |