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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 2D11E14000C X-Stat-Signature: w4n8tp1td5tw6tngefeezzegy4irzj19 X-Rspam-User: X-HE-Tag: 1764953948-496163 X-HE-Meta: U2FsdGVkX18+ifd6LWw7udBNcOcfDhAnbjAlK/36Bmdvfa0AnDO0kd57BomamSnRjiEXvqRD5Ibtbn0x6kDLqv18e6hKw0T9rJA/ya0UUdybclU+fUV42R+550Go5RXnr529qHjenX4Ki0lS9XYvE+1rtzMMCA6pUcH/4ciApT4ruvxEIBSP/WsHeqZYclKhIQ3W8zrDI2ONh2pmr2ncpGfwtpeMuYmjIpMgHcP7ruGdOxYe4AETOkiKROG4+ys3AL0RUsN+X8Fax//028MmW4d3u05/P4wd0aVYI70lh0pxcRvScqEU6CWNRF36pGJvZjXtH57AkMMGPss09VPpHABPV3Q1Ds5rVrN9H/QzBkF6cNqfYFo20aWySLUqW4kbRAC30jMX+1/XsJacz0iPQdxhGkcgHSEw+LKtvppTTFQqh0+gol9+Cf3jiISRlhUjD57fIss77HiVxarY0T8Him3GlhbSx4U4X1vlOfBpu/U5CLsM+l7TYSePF5ssnUMrd+/V9PjD+DJmdupzPZt39zpJQfUrVCCHnMffT1DTY4Qoz78N5p12WCh0EMM5m+GERZ4I0EU35BQaRT/5f6yBJa0EsxvQzPwxiFHZcDFUvHP1lRmR+6lB/fWti8UB7m9o2DlQueClRwZo0tVEedPysq0BSbn644YYeaBMW55vH4dvoyRg9gAVy3R2bDwU7Wm4YAYf3fZO441y8+3NUdI/y3U07vzmiOH6+DUdR0jVV6JRhQu4NEe1tx3fTRjTDA4mRvH4uAVQi9gTLeGcLpBE867Jih/qoNuz3TXfeztfISmPgKF52o1WD9VDWimaPOaz4M5mPwSOyJas4JelftqkWJ9ooPG+b+Jt0LjyYt/5ZNbdet5e8gLTAKpmgsA2KGn9E8qb36Y2afBe5URIkKi5e13ylr6rK27Xkm9OZifaX6UOVgjvhABFokqWQz0Dm5bMmlIRjCuoOAQhxnGRXIZ 8dVEd1Gw v6aeW6ImYdGU51rypWQdMsUCIpNabZn/r0iLQqoYqf8vIVyfbHFRggqY+svpX2yzW6tVq3VbLCDhIMRroH4AdbiWYEzVCuZz5GJnJQ67gxIDbwfosOm+GUWU/3nXg/TOkzm8lelP3B8ZR4Yyew40XB+uiuhERaSYLRj0SrJdK904Z2NCdef+gTWkbS/dwsXCvKSndvxc2ApvHKd9swVB+azihArcBX6G+Yq36HJaOw99+Le9GTGzegRuAdq87ifKkK5CHRorE3MYzHUIExVNqZtwCqoCMOgYPSnKBDbNESDk4UhFURnLXZwXBHziOOY9zXC5xKuVIgPYDbDTld1jE7su0d325tszd2moCLU5e4i4M9cA= 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, current defconfigs=0A= select for example CONFIG_RO_DATA_FULL_DEFAULT_ENABLED, which forces a 4k= =0A= 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=