[PATCH v7 048/102] KVM: x86/mmu: Disallow dirty logging for x86 TDX

isaku.yamahata
2022-06-27T21:59:13Z

From: Sean Christopherson <sean.j.christopherson@intel.com>

TDX doesn't support dirty logging. Report dirty logging isn't supported so
that device model, for example qemu, can properly handle it.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/x86.c | 5 +++++
include/linux/kvm_host.h | 1 +
virt/kvm/kvm_main.c | 15 ++++++++++++---
3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4309ef0ade21..dcd1f5e2ba05 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13164,6 +13164,11 @@ int kvm_sev_es_string_io(struct kvm_vcpu *vcpu, unsigned int size,
}
EXPORT_SYMBOL_GPL(kvm_sev_es_string_io);

+bool kvm_arch_dirty_log_supported(struct kvm *kvm)
+{
+ return kvm->arch.vm_type != KVM_X86_TDX_VM;
+}
+
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_entry);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_fast_mmio);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 79a4988fd51f..6fd8ec297236 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1452,6 +1452,7 @@ bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu);
int kvm_arch_post_init_vm(struct kvm *kvm);
void kvm_arch_pre_destroy_vm(struct kvm *kvm);
int kvm_arch_create_vm_debugfs(struct kvm *kvm);
+bool kvm_arch_dirty_log_supported(struct kvm *kvm);

#ifndef __KVM_HAVE_ARCH_VM_ALLOC
/*
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 7a5261eb7eb8..703c1d0c98da 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1467,9 +1467,18 @@ static void kvm_replace_memslot(struct kvm *kvm,
}
}

-static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem)
+bool __weak kvm_arch_dirty_log_supported(struct kvm *kvm)
{
- u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
+ return true;
+}
+
+static int check_memory_region_flags(struct kvm *kvm,
+ const struct kvm_userspace_memory_region *mem)
+{
+ u32 valid_flags = 0;
+
+ if (kvm_arch_dirty_log_supported(kvm))
+ valid_flags |= KVM_MEM_LOG_DIRTY_PAGES;

#ifdef __KVM_HAVE_READONLY_MEM
valid_flags |= KVM_MEM_READONLY;
@@ -1871,7 +1880,7 @@ int __kvm_set_memory_region(struct kvm *kvm,
int as_id, id;
int r;

- r = check_memory_region_flags(mem);
+ r = check_memory_region_flags(kvm, mem);
if (r)
return r;

--
2.25.1