Re: [PATCH 02/16] KVM: arm64: Don't issue CMOs when the physical address is invalid
From: Will Deacon <will@kernel.org>
Date: 2021-07-27 18:10:52
Also in:
kvm, kvmarm, lkml
On Thu, Jul 15, 2021 at 05:31:45PM +0100, Marc Zyngier wrote:
quoted hunk ↗ jump to hunk
Make sure we don't issue CMOs when mapping something that is not a memory address in the S2 page tables. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kvm/hyp/pgtable.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 05321f4165e3..a5874ebd0354 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c@@ -619,12 +619,16 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level, } /* Perform CMOs before installation of the guest stage-2 PTE */ - if (mm_ops->dcache_clean_inval_poc && stage2_pte_cacheable(pgt, new)) - mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops), - granule); - - if (mm_ops->icache_inval_pou && stage2_pte_executable(new)) - mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule); + if (kvm_phys_is_valid(phys)) { + if (mm_ops->dcache_clean_inval_poc && + stage2_pte_cacheable(pgt, new)) + mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, + mm_ops), + granule); + if (mm_ops->icache_inval_pou && stage2_pte_executable(new)) + mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), + granule); + }
Given that this check corresponds to checking the validity of 'new', I
wonder whether we'd be better off pushing the validity checks down into
stage2_pte_{cacheable,executable}()?
I.e. have stage2_pte_cacheable() return false if !kvm_pte_valid()
Will
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