linux-kernel - [PATCH v10 051/108] KVM: x86/mmu: Disallow dirty logging for x86 TDX

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Message-Id: <4873c5af293116df92eb8da5e1ba4e76df081682.1667110240.git.isaku.yamahata@intel.com>
Date:   Sat, 29 Oct 2022 23:22:52 -0700
From:   isaku.yamahata@...el.com
To:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     isaku.yamahata@...el.com, isaku.yamahata@...il.com,
        Paolo Bonzini <pbonzini@...hat.com>, erdemaktas@...gle.com,
        Sean Christopherson <seanjc@...gle.com>,
        Sagi Shahar <sagis@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: [PATCH v10 051/108] KVM: x86/mmu: Disallow dirty logging for x86 TDX

From: Isaku Yamahata <isaku.yamahata@...el.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@...el.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
Reviewed-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/x86.c       |  5 +++++
 include/linux/kvm_host.h |  1 +
 virt/kvm/kvm_main.c      | 10 +++++++++-
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ba4a9ce0ee80..24d9bfd4c582 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13862,6 +13862,11 @@ 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;
+}
+
 bool kvm_arch_has_private_mem(struct kvm *kvm)
 {
 	return kvm->arch.vm_type == KVM_X86_TDX_VM;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index b658803ea2c7..a0b64308d240 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1477,6 +1477,7 @@ int kvm_arch_drop_vm(int usage_count);
 void kvm_arch_pre_destroy_vm(struct kvm *kvm);
 int kvm_arch_create_vm_debugfs(struct kvm *kvm);
 bool kvm_arch_has_private_mem(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 8c996f40b544..9f82b03a8118 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1869,10 +1869,18 @@ bool __weak kvm_arch_has_private_mem(struct kvm *kvm)
 	return false;
 }
 
+bool __weak kvm_arch_dirty_log_supported(struct kvm *kvm)
+{
+	return true;
+}
+
 static int check_memory_region_flags(struct kvm *kvm,
 				     const struct kvm_user_mem_region *mem)
 {
-	u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
+	u32 valid_flags = 0;
+
+	if (kvm_arch_dirty_log_supported(kvm))
+		valid_flags |= KVM_MEM_LOG_DIRTY_PAGES;
 
 #ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM
 	if (kvm_arch_has_private_mem(kvm))
-- 
2.25.1