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AJvYcCWBculZoIaVPNTAi0AODmxpvAm5eNuakIbhzsUpi9/j9a4e4NROlvIwIPo9quzaQvNXqwAZAA+ltw==@kvack.org X-Gm-Message-State: AOJu0YyDnWUVQhp9z2u1dM8O0mgOT0wSvXakiUicuYE1FQWkibsJHTH5 820yAMLI2apLljBF+XCE0nyoGLG8dHCeO8+003C0njtZmQsONmvKV9nVl21sk5ncfSC2P6rftXN At0sN03y26CqmYfAFwyr/qjwURsqTvj74E5HB938B X-Gm-Gg: ASbGncvawsPSlTJ6QvHAkwNCqFCQUseJ34L4sVufuAO0F6gvKBmGTJplisr70wI7G5p VYOvWtHCUeHt8SYqjpNyrRm7+WwHn6HXmJj6+kKdX1aA67MgE93ZIujmsLtDg0WRQmzeLnN4iLp 9RsAPAtsKMCe3+uY9HRCJlooabQdEaJTV4XLdZSDfLhRHqVVkRpjF+keVywZdYKpd/ICytodEMu g== X-Google-Smtp-Source: AGHT+IHn5/wKNbQI7vSalTh67RacBOPcQxELVMGr9+xQc8VXWu2LJeEyltIok2m0x5MIgx3zLGdGw/XrfKms7dj72v4= X-Received: by 2002:a05:690c:998b:b0:70c:d256:e7fc with SMTP id 00721157ae682-710f76860c0mr3864297b3.21.1749144446771; Thu, 05 Jun 2025 10:27:26 -0700 (PDT) MIME-Version: 1.0 References: <20250605153800.557144-1-tabba@google.com> <20250605153800.557144-16-tabba@google.com> In-Reply-To: <20250605153800.557144-16-tabba@google.com> From: James Houghton Date: Thu, 5 Jun 2025 10:26:51 -0700 X-Gm-Features: AX0GCFsB1VCQwR2A3HvXMZ_dWbE-qcPDzOfRtnENxU5ylhm95m2ctpABU2Dvxt4 Message-ID: Subject: Re: [PATCH v11 15/18] KVM: arm64: Enable host mapping of shared guest_memfd memory To: Fuad Tabba Cc: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, kvmarm@lists.linux.dev, pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, peterx@redhat.com, pankaj.gupta@amd.com, ira.weiny@intel.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 368A240004 X-Stat-Signature: qponzs6ccksuhqp3wk9zmp7uhstydkw4 X-Rspam-User: X-HE-Tag: 1749144448-605839 X-HE-Meta: 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 UDVEIIHh UPNpYg9DGuQ5v9dytnILSStsjWSzDgEHFbHvFbz88ueW5zD/ieyNPZk3LTZExsfqceK3Co9ZDOiFDuwkiktqW5aD/65QXbTYSM6e4hMSRu29JBuYg3JrWpsAC6aNi/OtxIkeb54f2AGhkyLx8beStJwVW0cEm2CoK2aVrLdZ17sLfbwUXj20vdjgKPr+vgek2tD0VZ1Jwyr4yIKc6UWpSXRxExGII+m3tCeabbHjnDMzM23HHGO+gSFT/aLXMXXvcnL+tTD68rVPwBysFvVypFKfE44YXBE9Cp6IQC1ayuY4Q6Fh2vIRr7aTugRGh497iu/dmhbActWmt1NTgvRqj5Ns90tR+D1lwOMD0EWITQN8Bhvo= 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: On Thu, Jun 5, 2025 at 8:38=E2=80=AFAM Fuad Tabba wrote: > > Enable the host mapping of guest_memfd-backed memory on arm64. > > This applies to all current arm64 VM types that support guest_memfd. > Future VM types can restrict this behavior via the > kvm_arch_gmem_supports_shared_mem() hook if needed. > > Acked-by: David Hildenbrand > Signed-off-by: Fuad Tabba Feel free to add: Reviewed-by: James Houghton > --- > arch/arm64/include/asm/kvm_host.h | 5 +++++ > arch/arm64/kvm/Kconfig | 1 + > arch/arm64/kvm/mmu.c | 7 +++++++ > 3 files changed, 13 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/k= vm_host.h > index 08ba91e6fb03..8add94929711 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -1593,4 +1593,9 @@ static inline bool kvm_arch_has_irq_bypass(void) > return true; > } > > +#ifdef CONFIG_KVM_GMEM > +#define kvm_arch_supports_gmem(kvm) true > +#define kvm_arch_supports_gmem_shared_mem(kvm) IS_ENABLED(CONFIG_KVM_GME= M_SHARED_MEM) > +#endif Thanks! > + > #endif /* __ARM64_KVM_HOST_H__ */ > diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig > index 096e45acadb2..8c1e1964b46a 100644 > --- a/arch/arm64/kvm/Kconfig > +++ b/arch/arm64/kvm/Kconfig > @@ -38,6 +38,7 @@ menuconfig KVM > select HAVE_KVM_VCPU_RUN_PID_CHANGE > select SCHED_INFO > select GUEST_PERF_EVENTS if PERF_EVENTS > + select KVM_GMEM_SHARED_MEM > help > Support hosting virtualized guest machines. > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > index f14925fe6144..19aca1442bbf 100644 > --- a/arch/arm64/kvm/mmu.c > +++ b/arch/arm64/kvm/mmu.c > @@ -2281,6 +2281,13 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm= , > if ((new->base_gfn + new->npages) > (kvm_phys_size(&kvm->arch.mmu= ) >> PAGE_SHIFT)) > return -EFAULT; > > + /* > + * Only support guest_memfd backed memslots with shared memory, s= ince > + * there aren't any CoCo VMs that support only private memory on = arm64. > + */ > + if (kvm_slot_has_gmem(new) && !kvm_gmem_memslot_supports_shared(n= ew)) > + return -EINVAL; > + > hva =3D new->userspace_addr; > reg_end =3D hva + (new->npages << PAGE_SHIFT); > > -- > 2.49.0.1266.g31b7d2e469-goog >