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/mm/physaddr.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 arch/mips/mm/physaddr.c (limited to 'arch/mips/mm/physaddr.c') diff --git a/arch/mips/mm/physaddr.c b/arch/mips/mm/physaddr.c new file mode 100644 index 000000000..a6b1bf820 --- /dev/null +++ b/arch/mips/mm/physaddr.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +static inline bool __debug_virt_addr_valid(unsigned long x) +{ + /* + * MAX_DMA_ADDRESS is a virtual address that may not correspond to an + * actual physical address. Enough code relies on + * virt_to_phys(MAX_DMA_ADDRESS) that we just need to work around it + * and always return true. + */ + if (x == MAX_DMA_ADDRESS) + return true; + + return x >= PAGE_OFFSET && (KSEGX(x) < KSEG2 || + IS_ENABLED(CONFIG_EVA) || + !IS_ENABLED(CONFIG_HIGHMEM)); +} + +phys_addr_t __virt_to_phys(volatile const void *x) +{ + WARN(!__debug_virt_addr_valid((unsigned long)x), + "virt_to_phys used for non-linear address: %p (%pS)\n", + x, x); + + return __virt_to_phys_nodebug(x); +} +EXPORT_SYMBOL(__virt_to_phys); + +phys_addr_t __phys_addr_symbol(unsigned long x) +{ + /* This is bounds checking against the kernel image only. + * __pa_symbol should only be used on kernel symbol addresses. + */ + VIRTUAL_BUG_ON(x < (unsigned long)_text || + x > (unsigned long)_end); + + return __pa_symbol_nodebug(x); +} +EXPORT_SYMBOL(__phys_addr_symbol); -- cgit v1.3.1