2022-03-04 20:13:55

by Isaku Yamahata

Subject: [RFC PATCH v5 035/104] KVM: x86/mmu: Disallow dirty logging for x86 TDX

From: Sean Christopherson <[email protected]>

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 <[email protected]>
Signed-off-by: Xiaoyao Li <[email protected]>
Signed-off-by: Isaku Yamahata <[email protected]>
---
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 c52a052e208c..da411bcd8cbc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12876,6 +12876,11 @@ 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 a56044a31bc6..86f984e0c93f 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1423,6 +1423,7 @@ 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 3adee9c6b370..ae3bf553f215 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1423,9 +1423,18 @@ 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;
@@ -1826,7 +1835,7 @@ 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

2022-04-06 12:52:21

by Paolo Bonzini

Subject: Re: [RFC PATCH v5 035/104] KVM: x86/mmu: Disallow dirty logging for x86 TDX

On 3/4/22 20:48, [email protected] wrote:
> From: Sean Christopherson <[email protected]>
>
> 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 <[email protected]>
> Signed-off-by: Xiaoyao Li <[email protected]>
> Signed-off-by: Isaku Yamahata <[email protected]>
> ---
> 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 c52a052e208c..da411bcd8cbc 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -12876,6 +12876,11 @@ 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 a56044a31bc6..86f984e0c93f 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -1423,6 +1423,7 @@ 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 3adee9c6b370..ae3bf553f215 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1423,9 +1423,18 @@ 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;
> @@ -1826,7 +1835,7 @@ 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;
>

Reviewed-by: Paolo Bonzini <[email protected]>