On Thu, 5 Jun 2025 at 16:49, David Hildenbrand <david@xxxxxxxxxx> wrote: > > On 05.06.25 17:37, Fuad Tabba wrote: > > 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 > > Is $subject and this still true, given that it's now also supported for > KVM_X86_DEFAULT_VM? True, just not the whole truth :) I guess a better one would be, for Software VMs (remove protected)? /fuad > -- > Cheers, > > David / dhildenb >
