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authorPaolo Bonzini <pbonzini@redhat.com>2024-03-09 19:48:35 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2024-03-09 19:48:35 +0300
commit7d8942d8e73843de35b3737b8be50f8fef6796bb (patch)
tree593e26864092f6829b25a1847cb5e2172ae7de53 /virt
parent0cbca1bf44a0b8666c91ce3438f235c6fe70fbf1 (diff)
parent2dfd2383034421101300a3b7325cf339a182d218 (diff)
downloadlinux-7d8942d8e73843de35b3737b8be50f8fef6796bb.tar.xz
Merge tag 'kvm-x86-guest_memfd_fixes-6.8' of https://github.com/kvm-x86/linux into HEAD
KVM GUEST_MEMFD fixes for 6.8: - Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY to avoid creating ABI that KVM can't sanely support. - Update documentation for KVM_SW_PROTECTED_VM to make it abundantly clear that such VMs are purely a development and testing vehicle, and come with zero guarantees. - Limit KVM_SW_PROTECTED_VM guests to the TDP MMU, as the long term plan is to support confidential VMs with deterministic private memory (SNP and TDX) only in the TDP MMU. - Fix a bug in a GUEST_MEMFD negative test that resulted in false passes when verifying that KVM_MEM_GUEST_MEMFD memslots can't be dirty logged.
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/kvm_main.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ff588677beb7..054d20ec61b9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1615,7 +1615,13 @@ static int check_memory_region_flags(struct kvm *kvm,
valid_flags &= ~KVM_MEM_LOG_DIRTY_PAGES;
#ifdef CONFIG_HAVE_KVM_READONLY_MEM
- valid_flags |= KVM_MEM_READONLY;
+ /*
+ * GUEST_MEMFD is incompatible with read-only memslots, as writes to
+ * read-only memslots have emulated MMIO, not page fault, semantics,
+ * and KVM doesn't allow emulated MMIO for private memory.
+ */
+ if (!(mem->flags & KVM_MEM_GUEST_MEMFD))
+ valid_flags |= KVM_MEM_READONLY;
#endif
if (mem->flags & ~valid_flags)