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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Stat-Signature: 1i47mu8q8ejmkounbsabnuj1zf5n7oyk X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 2F90140009 X-HE-Tag: 1769446227-743946 X-HE-Meta: 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 SshLiWBq 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 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= 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 ac7f970c7883..d431ca7d4fc9 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= @@ -1654,5 +1655,17 @@ 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(void)=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= #endif /* __ARM64_KVM_HOST_H__ */=0A= -- =0A= 2.50.1=0A= =0A=