Define the architecture-specific macro to enable shared memory support in guest_memfd for relevant software-only VM types, specifically KVM_X86_DEFAULT_VM and KVM_X86_SW_PROTECTED_VM. Enable the KVM_GMEM_SHARED_MEM Kconfig option if KVM_SW_PROTECTED_VM is enabled. Co-developed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx> Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx> Signed-off-by: Fuad Tabba <tabba@xxxxxxxxxx> --- arch/x86/include/asm/kvm_host.h | 10 ++++++++++ arch/x86/kvm/Kconfig | 1 + arch/x86/kvm/x86.c | 3 ++- 3 files changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 709cc2a7ba66..ce9ad4cd93c5 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -2255,8 +2255,18 @@ void kvm_configure_mmu(bool enable_tdp, int tdp_forced_root_level, #ifdef CONFIG_KVM_GMEM #define kvm_arch_supports_gmem(kvm) ((kvm)->arch.supports_gmem) + +/* + * CoCo VMs with hardware support that use guest_memfd only for backing private + * memory, e.g., TDX, cannot use guest_memfd with userspace mapping enabled. + */ +#define kvm_arch_supports_gmem_shared_mem(kvm) \ + (IS_ENABLED(CONFIG_KVM_GMEM_SHARED_MEM) && \ + ((kvm)->arch.vm_type == KVM_X86_SW_PROTECTED_VM || \ + (kvm)->arch.vm_type == KVM_X86_DEFAULT_VM)) #else #define kvm_arch_supports_gmem(kvm) false +#define kvm_arch_supports_gmem_shared_mem(kvm) false #endif #define kvm_arch_has_readonly_mem(kvm) (!(kvm)->arch.has_protected_state) diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index b37258253543..fdf24b50af9d 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -47,6 +47,7 @@ config KVM_X86 select KVM_GENERIC_HARDWARE_ENABLING select KVM_GENERIC_PRE_FAULT_MEMORY select KVM_GENERIC_GMEM_POPULATE if KVM_SW_PROTECTED_VM + select KVM_GMEM_SHARED_MEM if KVM_SW_PROTECTED_VM select KVM_WERROR if WERROR config KVM diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 035ced06b2dd..2a02f2457c42 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -12718,7 +12718,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type) return -EINVAL; kvm->arch.vm_type = type; - kvm->arch.supports_gmem = (type == KVM_X86_SW_PROTECTED_VM); + kvm->arch.supports_gmem = + type == KVM_X86_DEFAULT_VM || type == KVM_X86_SW_PROTECTED_VM; /* Decided by the vendor code for other VM types. */ kvm->arch.pre_fault_allowed = type == KVM_X86_DEFAULT_VM || type == KVM_X86_SW_PROTECTED_VM; -- 2.49.0.1266.g31b7d2e469-goog
