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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: B87FF180006 X-Stat-Signature: op1yobwm3b8b7393u4oefu88co8pp19g X-Rspam-User: X-HE-Tag: 1773756739-650399 X-HE-Meta: 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 4Z47hMJe D2Iw4GSuTLHtv7f02uEgQVpSfP3brS+p0Rb0En1oXaf98eTQVJag5Nfhy9k68Mc23Zs442+gVA1lR9C1ZpxIhxjPlZDTnhy58Cqp71iwck9yPymXyLcpj3gfsN9z97F/py3aulkcTKSwlmTTwe7Fx8PPYEtD/vgDeNpceSutK8MwWEm/22CxnFHFRh5qNai4hNNiBPIjcm1Vx/4O+SToGJm5Ffn43PdOaQJ+zFzopW1YeLJqlMBmrYX9VZ2K9k+DJNlhgh4kBAkwlSO/I55c0j6OlE54xrMBXCr/mBLwxj8Hj8VRmowEyJH85Ba/TcJWc/A4inWWivqchD9lqwCpJkjxhKzYMNoYZ8+HGKhMLdfT+wV4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Patrick Roy =0A= =0A= Support for GUEST_MEMFD_FLAG_NO_DIRECT_MAP on arm64 depends on 1) direct=0A= map manipulations at 4k granularity being possible, and 2) FEAT_S2FWB.=0A= =0A= 1) is met whenever the direct map is set up at 4k granularity (e.g. not=0A= with huge/gigantic pages) at boottime, as due to ARM's=0A= break-before-make semantics, breaking huge mappings into 4k mappings in=0A= the direct map is not possible (BBM would require temporary invalidation=0A= of the entire huge mapping, even if only a 4k subrange should be zapped,=0A= which will probably crash the kernel). However, the current default for=0A= rodata_full is true, which forces a 4k direct map.=0A= =0A= 2) is required to allow KVM to elide cache coherency operations when=0A= installing stage 2 page tables, which require the direct map to be=0A= entry for the newly mapped memory to be present (which it will not be,=0A= as guest_memfd would have removed direct map entries in=0A= kvm_gmem_get_pfn()).=0A= =0A= Cc: Will Deacon =0A= Signed-off-by: Patrick Roy =0A= Reviewed-by: David Hildenbrand (Arm) =0A= Signed-off-by: Nikita Kalyazin =0A= ---=0A= arch/arm64/include/asm/kvm_host.h | 13 +++++++++++++=0A= 1 file changed, 13 insertions(+)=0A= =0A= diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm= _host.h=0A= index 70cb9cfd760a..fbdd43e7e94e 100644=0A= --- a/arch/arm64/include/asm/kvm_host.h=0A= +++ b/arch/arm64/include/asm/kvm_host.h=0A= @@ -19,6 +19,7 @@=0A= #include =0A= #include =0A= #include =0A= +#include =0A= #include =0A= #include =0A= #include =0A= @@ -1682,6 +1683,18 @@ static __always_inline enum fgt_group_id __fgt_reg_t= o_group_id(enum vcpu_sysreg=0A= \=0A= p; \=0A= })=0A= +#ifdef CONFIG_KVM_GUEST_MEMFD=0A= +static inline bool kvm_arch_gmem_supports_no_direct_map(struct kvm *kvm)= =0A= +{=0A= + /*=0A= + * Without FWB, direct map access is needed in kvm_pgtable_stage2_map(),= =0A= + * as it calls dcache_clean_inval_poc().=0A= + */=0A= + return can_set_direct_map() && cpus_have_final_cap(ARM64_HAS_STAGE2_FWB);= =0A= +}=0A= +#define kvm_arch_gmem_supports_no_direct_map kvm_arch_gmem_supports_no_dir= ect_map=0A= +#endif /* CONFIG_KVM_GUEST_MEMFD */=0A= +=0A= =0A= long kvm_get_cap_for_kvm_ioctl(unsigned int ioctl, long *ext);=0A= =0A= -- =0A= 2.50.1=0A= =0A=