Enable mapping guest_memfd backed memory at the host in arm64. For now, it applies to all arm64 VM types in arm64 that use guest_memfd. In the future, new VM types can restrict this via kvm_arch_gmem_supports_shared_mem(). Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx> --- 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/kvm_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_GMEM_SHARED_MEM) +#endif + #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 896c56683d88..03da08390bf0 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -2264,6 +2264,13 @@ 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, since + * there aren't any CoCo VMs that support only private memory on arm64. + */ + if (kvm_slot_has_gmem(new) && !kvm_gmem_memslot_supports_shared(new)) + return -EINVAL; + hva = new->userspace_addr; reg_end = hva + (new->npages << PAGE_SHIFT); -- 2.49.0.1164.gab81da1b16-goog
