diff mbox series

[v19,016/130] KVM: x86/mmu: Introduce kvm_mmu_map_tdp_page() for use by TDX

Message ID b2b7eeb1bab4cbf5421bf18647357a59b472dabe.1708933498.git.isaku.yamahata@intel.com (mailing list archive)
State New, archived
Headers show
Series [v19,001/130] x86/virt/tdx: Rename _offset to _member for TD_SYSINFO_MAP() macro | expand

Commit Message

Isaku Yamahata Feb. 26, 2024, 8:25 a.m. UTC
From: Sean Christopherson <sean.j.christopherson@intel.com>

Introduce a helper to directly (pun intended) fault-in a TDP page
without having to go through the full page fault path.  This allows
TDX to get the resulting pfn and also allows the RET_PF_* enums to
stay in mmu.c where they belong.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
v19:
- Move up for KVM_MEMORY_MAPPING.
- Add goal_level for the caller to know how many pages are mapped.

v14 -> v15:
- Remove loop in kvm_mmu_map_tdp_page() and return error code based on
  RET_FP_xxx value to avoid potential infinite loop.  The caller should
  loop on -EAGAIN instead now.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
 arch/x86/kvm/mmu.h     |  3 +++
 arch/x86/kvm/mmu/mmu.c | 58 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

Comments

Binbin Wu March 6, 2024, 7:13 a.m. UTC | #1
On 2/26/2024 4:25 PM, isaku.yamahata@intel.com wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> Introduce a helper to directly (pun intended) fault-in a TDP page
> without having to go through the full page fault path.  This allows
> TDX to get the resulting pfn and also allows the RET_PF_* enums to
> stay in mmu.c where they belong.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
> v19:
> - Move up for KVM_MEMORY_MAPPING.
> - Add goal_level for the caller to know how many pages are mapped.
>
> v14 -> v15:
> - Remove loop in kvm_mmu_map_tdp_page() and return error code based on
>    RET_FP_xxx value to avoid potential infinite loop.  The caller should
>    loop on -EAGAIN instead now.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
>   arch/x86/kvm/mmu.h     |  3 +++
>   arch/x86/kvm/mmu/mmu.c | 58 ++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 61 insertions(+)
>
> diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
> index 60f21bb4c27b..d96c93a25b3b 100644
> --- a/arch/x86/kvm/mmu.h
> +++ b/arch/x86/kvm/mmu.h
> @@ -183,6 +183,9 @@ static inline void kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu,
>   	__kvm_mmu_refresh_passthrough_bits(vcpu, mmu);
>   }
>   
> +int kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code,
> +			 u8 max_level, u8 *goal_level);
> +
>   /*
>    * Check if a given access (described through the I/D, W/R and U/S bits of a
>    * page fault error code pfec) causes a permission fault with the given PTE
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index 61674d6b17aa..ca0c91f14063 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -4615,6 +4615,64 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
>   	return direct_page_fault(vcpu, fault);
>   }
>   
> +int kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code,
> +			 u8 max_level, u8 *goal_level)
> +{
> +	int r;
> +	struct kvm_page_fault fault = (struct kvm_page_fault) {
> +		.addr = gpa,
> +		.error_code = error_code,
> +		.exec = error_code & PFERR_FETCH_MASK,
> +		.write = error_code & PFERR_WRITE_MASK,
> +		.present = error_code & PFERR_PRESENT_MASK,
> +		.rsvd = error_code & PFERR_RSVD_MASK,
> +		.user = error_code & PFERR_USER_MASK,
> +		.prefetch = false,
> +		.is_tdp = true,
> +		.is_private = error_code & PFERR_GUEST_ENC_MASK,
> +		.nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(vcpu->kvm),
> +	};
> +
> +	WARN_ON_ONCE(!vcpu->arch.mmu->root_role.direct);
> +	fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
> +
> +	r = mmu_topup_memory_caches(vcpu, false);

Does it need a cache topup here?
Both kvm_tdp_mmu_page_fault() and direct_page_fault() will call
mmu_topup_memory_caches() when needed.

> +	if (r)
> +		return r;
> +
> +	fault.max_level = max_level;
> +	fault.req_level = PG_LEVEL_4K;
> +	fault.goal_level = PG_LEVEL_4K;
> +
> +#ifdef CONFIG_X86_64
> +	if (tdp_mmu_enabled)
> +		r = kvm_tdp_mmu_page_fault(vcpu, &fault);
> +	else
> +#endif
> +		r = direct_page_fault(vcpu, &fault);
> +
> +	if (is_error_noslot_pfn(fault.pfn) || vcpu->kvm->vm_bugged)
> +		return -EFAULT;
> +
> +	switch (r) {
> +	case RET_PF_RETRY:
> +		return -EAGAIN;
> +
> +	case RET_PF_FIXED:
> +	case RET_PF_SPURIOUS:
> +		if (goal_level)
> +			*goal_level = fault.goal_level;
> +		return 0;
> +
> +	case RET_PF_CONTINUE:
> +	case RET_PF_EMULATE:
> +	case RET_PF_INVALID:
> +	default:
> +		return -EIO;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(kvm_mmu_map_tdp_page);
> +
>   static void nonpaging_init_context(struct kvm_mmu *context)
>   {
>   	context->page_fault = nonpaging_page_fault;
Isaku Yamahata March 6, 2024, 10:22 p.m. UTC | #2
On Wed, Mar 06, 2024 at 03:13:22PM +0800,
Binbin Wu <binbin.wu@linux.intel.com> wrote:

> 
> 
> On 2/26/2024 4:25 PM, isaku.yamahata@intel.com wrote:
> > From: Sean Christopherson <sean.j.christopherson@intel.com>
> > 
> > Introduce a helper to directly (pun intended) fault-in a TDP page
> > without having to go through the full page fault path.  This allows
> > TDX to get the resulting pfn and also allows the RET_PF_* enums to
> > stay in mmu.c where they belong.
> > 
> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> > ---
> > v19:
> > - Move up for KVM_MEMORY_MAPPING.
> > - Add goal_level for the caller to know how many pages are mapped.
> > 
> > v14 -> v15:
> > - Remove loop in kvm_mmu_map_tdp_page() and return error code based on
> >    RET_FP_xxx value to avoid potential infinite loop.  The caller should
> >    loop on -EAGAIN instead now.
> > 
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> > ---
> >   arch/x86/kvm/mmu.h     |  3 +++
> >   arch/x86/kvm/mmu/mmu.c | 58 ++++++++++++++++++++++++++++++++++++++++++
> >   2 files changed, 61 insertions(+)
> > 
> > diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
> > index 60f21bb4c27b..d96c93a25b3b 100644
> > --- a/arch/x86/kvm/mmu.h
> > +++ b/arch/x86/kvm/mmu.h
> > @@ -183,6 +183,9 @@ static inline void kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu,
> >   	__kvm_mmu_refresh_passthrough_bits(vcpu, mmu);
> >   }
> > +int kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code,
> > +			 u8 max_level, u8 *goal_level);
> > +
> >   /*
> >    * Check if a given access (described through the I/D, W/R and U/S bits of a
> >    * page fault error code pfec) causes a permission fault with the given PTE
> > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> > index 61674d6b17aa..ca0c91f14063 100644
> > --- a/arch/x86/kvm/mmu/mmu.c
> > +++ b/arch/x86/kvm/mmu/mmu.c
> > @@ -4615,6 +4615,64 @@ int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
> >   	return direct_page_fault(vcpu, fault);
> >   }
> > +int kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code,
> > +			 u8 max_level, u8 *goal_level)
> > +{
> > +	int r;
> > +	struct kvm_page_fault fault = (struct kvm_page_fault) {
> > +		.addr = gpa,
> > +		.error_code = error_code,
> > +		.exec = error_code & PFERR_FETCH_MASK,
> > +		.write = error_code & PFERR_WRITE_MASK,
> > +		.present = error_code & PFERR_PRESENT_MASK,
> > +		.rsvd = error_code & PFERR_RSVD_MASK,
> > +		.user = error_code & PFERR_USER_MASK,
> > +		.prefetch = false,
> > +		.is_tdp = true,
> > +		.is_private = error_code & PFERR_GUEST_ENC_MASK,
> > +		.nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(vcpu->kvm),
> > +	};
> > +
> > +	WARN_ON_ONCE(!vcpu->arch.mmu->root_role.direct);
> > +	fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
> > +
> > +	r = mmu_topup_memory_caches(vcpu, false);
> 
> Does it need a cache topup here?
> Both kvm_tdp_mmu_page_fault() and direct_page_fault() will call
> mmu_topup_memory_caches() when needed.

You're right. As the called function has changed, I missed to remove it.
diff mbox series

Patch

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 60f21bb4c27b..d96c93a25b3b 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -183,6 +183,9 @@  static inline void kvm_mmu_refresh_passthrough_bits(struct kvm_vcpu *vcpu,
 	__kvm_mmu_refresh_passthrough_bits(vcpu, mmu);
 }
 
+int kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code,
+			 u8 max_level, u8 *goal_level);
+
 /*
  * Check if a given access (described through the I/D, W/R and U/S bits of a
  * page fault error code pfec) causes a permission fault with the given PTE
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 61674d6b17aa..ca0c91f14063 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4615,6 +4615,64 @@  int kvm_tdp_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 	return direct_page_fault(vcpu, fault);
 }
 
+int kvm_mmu_map_tdp_page(struct kvm_vcpu *vcpu, gpa_t gpa, u64 error_code,
+			 u8 max_level, u8 *goal_level)
+{
+	int r;
+	struct kvm_page_fault fault = (struct kvm_page_fault) {
+		.addr = gpa,
+		.error_code = error_code,
+		.exec = error_code & PFERR_FETCH_MASK,
+		.write = error_code & PFERR_WRITE_MASK,
+		.present = error_code & PFERR_PRESENT_MASK,
+		.rsvd = error_code & PFERR_RSVD_MASK,
+		.user = error_code & PFERR_USER_MASK,
+		.prefetch = false,
+		.is_tdp = true,
+		.is_private = error_code & PFERR_GUEST_ENC_MASK,
+		.nx_huge_page_workaround_enabled = is_nx_huge_page_enabled(vcpu->kvm),
+	};
+
+	WARN_ON_ONCE(!vcpu->arch.mmu->root_role.direct);
+	fault.slot = kvm_vcpu_gfn_to_memslot(vcpu, fault.gfn);
+
+	r = mmu_topup_memory_caches(vcpu, false);
+	if (r)
+		return r;
+
+	fault.max_level = max_level;
+	fault.req_level = PG_LEVEL_4K;
+	fault.goal_level = PG_LEVEL_4K;
+
+#ifdef CONFIG_X86_64
+	if (tdp_mmu_enabled)
+		r = kvm_tdp_mmu_page_fault(vcpu, &fault);
+	else
+#endif
+		r = direct_page_fault(vcpu, &fault);
+
+	if (is_error_noslot_pfn(fault.pfn) || vcpu->kvm->vm_bugged)
+		return -EFAULT;
+
+	switch (r) {
+	case RET_PF_RETRY:
+		return -EAGAIN;
+
+	case RET_PF_FIXED:
+	case RET_PF_SPURIOUS:
+		if (goal_level)
+			*goal_level = fault.goal_level;
+		return 0;
+
+	case RET_PF_CONTINUE:
+	case RET_PF_EMULATE:
+	case RET_PF_INVALID:
+	default:
+		return -EIO;
+	}
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_map_tdp_page);
+
 static void nonpaging_init_context(struct kvm_mmu *context)
 {
 	context->page_fault = nonpaging_page_fault;