linux-kernel - [PATCH v8 046/103] KVM: x86/mmu: Disallow dirty logging for x86 TDX

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Message-Id: <e44af3e75cde88c828bce875062dee7ab82960a6.1659854790.git.isaku.yamahata@intel.com>
Date:   Sun,  7 Aug 2022 15:01:31 -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>
Subject: [PATCH v8 046/103] 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      | 15 ++++++++++++---
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 702012f56502..972262ddda5d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -13356,6 +13356,11 @@ 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 63d4e3ce3e53..025251806e70 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1448,6 +1448,7 @@ 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 c44e5d7d418f..3cc29fdba562 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1511,9 +1511,18 @@ 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;
@@ -1915,7 +1924,7 @@ 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