diff options
| author | Marc Zyngier <maz@kernel.org> | 2021-08-06 12:31:08 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2021-08-20 09:12:24 +0100 |
| commit | cf364e08ea1c5dd217afb658d510aaef7d0cc6f4 (patch) | |
| tree | 73d252192060ec25e5dce98cc87edfdfdd7cf1b9 | |
| parent | 4efc0ede4f31d7ec25c3dee0c8f07f93735cee6d (diff) | |
KVM: arm64: Upgrade VMID accesses to {READ,WRITE}_ONCE
Since TLB invalidation can run in parallel with VMID allocation,
we need to be careful and avoid any sort of load/store tearing.
Use {READ,WRITE}_ONCE consistently to avoid any surprise.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jade Alglave <jade.alglave@arm.com>
Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Link: https://lore.kernel.org/r/20210806113109.2475-6-will@kernel.org
| -rw-r--r-- | arch/arm64/include/asm/kvm_mmu.h | 7 | ||||
| -rw-r--r-- | arch/arm64/kvm/arm.c | 2 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/nvhe/mem_protect.c | 4 | ||||
| -rw-r--r-- | arch/arm64/kvm/mmu.c | 2 |
4 files changed, 10 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 08bc81f6944b..02d378887743 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -252,6 +252,11 @@ static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa, #define kvm_phys_to_vttbr(addr) phys_to_ttbr(addr) +/* + * When this is (directly or indirectly) used on the TLB invalidation + * path, we rely on a previously issued DSB so that page table updates + * and VMID reads are correctly ordered. + */ static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu) { struct kvm_vmid *vmid = &mmu->vmid; @@ -259,7 +264,7 @@ static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu) u64 cnp = system_supports_cnp() ? VTTBR_CNP_BIT : 0; baddr = mmu->pgd_phys; - vmid_field = (u64)vmid->vmid << VTTBR_VMID_SHIFT; + vmid_field = (u64)READ_ONCE(vmid->vmid) << VTTBR_VMID_SHIFT; return kvm_phys_to_vttbr(baddr) | vmid_field | cnp; } diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index e9a2b8f27792..658f76067f46 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -571,7 +571,7 @@ static void update_vmid(struct kvm_vmid *vmid) kvm_call_hyp(__kvm_flush_vm_context); } - vmid->vmid = kvm_next_vmid; + WRITE_ONCE(vmid->vmid, kvm_next_vmid); kvm_next_vmid++; kvm_next_vmid &= (1 << kvm_get_vmid_bits()) - 1; diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 36aea13c9e5a..7a0c4af186a0 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -109,8 +109,8 @@ int kvm_host_prepare_stage2(void *pgt_pool_base) mmu->pgd_phys = __hyp_pa(host_kvm.pgt.pgd); mmu->arch = &host_kvm.arch; mmu->pgt = &host_kvm.pgt; - mmu->vmid.vmid_gen = 0; - mmu->vmid.vmid = 0; + WRITE_ONCE(mmu->vmid.vmid_gen, 0); + WRITE_ONCE(mmu->vmid.vmid, 0); return 0; } diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 0625bf2353c2..d9152717cbd9 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -485,7 +485,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu) mmu->arch = &kvm->arch; mmu->pgt = pgt; mmu->pgd_phys = __pa(pgt->pgd); - mmu->vmid.vmid_gen = 0; + WRITE_ONCE(mmu->vmid.vmid_gen, 0); return 0; out_destroy_pgtable: |