[PATCH 13/18] KVM: x86/mmu: Avoid warning when installing non-private memory attributes
From: Nicolas Saenz Julienne <hidden>
Date: 2024-06-09 15:57:30
Also in:
kvm, linux-arch, linux-doc, linux-trace-kernel, lkml
Subsystem:
kernel virtual machine (kvm), kernel virtual machine for x86 (kvm/x86), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Paolo Bonzini, Sean Christopherson, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
In preparation to introducing RWX memory attributes, make sure user-space is attempting to install a memory attribute with KVM_MEMORY_ATTRIBUTE_PRIVATE before throwing a warning on systems with no private memory support. Signed-off-by: Nicolas Saenz Julienne <redacted> --- arch/x86/kvm/mmu/mmu.c | 8 ++++++-- virt/kvm/kvm_main.c | 1 + 2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index b0c210b96419f..d56c04fbdc66b 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c@@ -7359,6 +7359,9 @@ void kvm_mmu_pre_destroy_vm(struct kvm *kvm) bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, struct kvm_gfn_range *range) { + unsigned long attrs = range->arg.attributes; + bool priv_attr = attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; + /* * Zap SPTEs even if the slot can't be mapped PRIVATE. KVM x86 only * supports KVM_MEMORY_ATTRIBUTE_PRIVATE, and so it *seems* like KVM
@@ -7370,7 +7373,7 @@ bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm, * Zapping SPTEs in this case ensures KVM will reassess whether or not * a hugepage can be used for affected ranges. */ - if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm))) + if (WARN_ON_ONCE(priv_attr && !kvm_arch_has_private_mem(kvm))) return false; return kvm_unmap_gfn_range(kvm, range);
@@ -7415,6 +7418,7 @@ bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, struct kvm_gfn_range *range) { unsigned long attrs = range->arg.attributes; + bool priv_attr = attrs & KVM_MEMORY_ATTRIBUTE_PRIVATE; struct kvm_memory_slot *slot = range->slot; int level;
@@ -7427,7 +7431,7 @@ bool kvm_arch_post_set_memory_attributes(struct kvm *kvm, * a range that has PRIVATE GFNs, and conversely converting a range to * SHARED may now allow hugepages. */ - if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm))) + if (WARN_ON_ONCE(priv_attr && !kvm_arch_has_private_mem(kvm))) return false; /*
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 14841acb8b959..63c4b6739edee 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c@@ -2506,6 +2506,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end, struct kvm_mmu_notifier_range pre_set_range = { .start = start, .end = end, + .arg.attributes = attributes, .handler = kvm_pre_set_memory_attributes, .on_lock = kvm_mmu_invalidate_begin, .flush_on_ret = true,
--
2.40.1