On 21.05.25 12:12, Fuad Tabba wrote:
Hi David,
On Wed, 21 May 2025 at 09:05, David Hildenbrand <david@xxxxxxxxxx> wrote:
On 13.05.25 18:34, Fuad Tabba wrote:
Enable mapping guest_memfd in arm64. For now, it applies to all
VMs 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 | 10 ++++++++++
arch/arm64/kvm/Kconfig | 1 +
2 files changed, 11 insertions(+)
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 08ba91e6fb03..2514779f5131 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1593,4 +1593,14 @@ static inline bool kvm_arch_has_irq_bypass(void)
return true;
}
+static inline bool kvm_arch_supports_gmem(struct kvm *kvm)
+{
+ return IS_ENABLED(CONFIG_KVM_GMEM);
+}
+
+static inline bool kvm_arch_vm_supports_gmem_shared_mem(struct kvm *kvm)
+{
+ return IS_ENABLED(CONFIG_KVM_GMEM_SHARED_MEM);
+}
+
#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.
Do we have to reject somewhere if we are given a guest_memfd that was
*not* created using the SHARED flag? Or will existing checks already
reject that?
We don't reject, but I don't think we need to. A user can create a
guest_memfd that's private in arm64, it would just be useless.
But the arm64 fault routine would not be able to handle that properly, no?
--
Cheers,
David / dhildenb
