[RFC PATCH 7/8] KVM: x86: Add hooks in kvm_arch_vcpu_map_memory()

isaku.yamahata
2024-03-01T17:29:47Z

From: Isaku Yamahata <isaku.yamahata@intel.com>

In the case of TDX, the memory contents needs to be provided to be
encrypted when populating guest memory before running the guest. Add hooks
in kvm_mmu_map_tdp_page() for KVM_MAP_MEMORY before/after calling
kvm_mmu_tdp_page(). TDX KVM will use the hooks.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
arch/x86/include/asm/kvm-x86-ops.h | 2 ++
arch/x86/include/asm/kvm_host.h | 6 ++++++
arch/x86/kvm/x86.c | 34 ++++++++++++++++++++++++++++++
3 files changed, 42 insertions(+)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index 3942b74c1b75..fc4e11d40733 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -137,6 +137,8 @@ KVM_X86_OP(complete_emulated_msr)
KVM_X86_OP(vcpu_deliver_sipi_vector)
KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons);
KVM_X86_OP_OPTIONAL(get_untagged_addr)
+KVM_X86_OP_OPTIONAL(pre_mmu_map_page);
+KVM_X86_OP_OPTIONAL(post_mmu_map_page);

#undef KVM_X86_OP
#undef KVM_X86_OP_OPTIONAL
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 9e7b1a00e265..301fedd6b156 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1805,6 +1805,12 @@ struct kvm_x86_ops {
unsigned long (*vcpu_get_apicv_inhibit_reasons)(struct kvm_vcpu *vcpu);

gva_t (*get_untagged_addr)(struct kvm_vcpu *vcpu, gva_t gva, unsigned int flags);
+
+ int (*pre_mmu_map_page)(struct kvm_vcpu *vcpu,
+ struct kvm_memory_mapping *mapping,
+ u32 *error_code, u8 *max_level);
+ void (*post_mmu_map_page)(struct kvm_vcpu *vcpu,
+ struct kvm_memory_mapping *mapping);
};

struct kvm_x86_nested_ops {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6025c0e12d89..ba8bf35f1c9a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5811,6 +5811,36 @@ int kvm_arch_vcpu_pre_map_memory(struct kvm_vcpu *vcpu)
return kvm_mmu_reload(vcpu);
}

+static int kvm_pre_mmu_map_page(struct kvm_vcpu *vcpu,
+ struct kvm_memory_mapping *mapping,
+ u32 error_code, u8 *max_level)
+{
+ int r = 0;
+
+ if (vcpu->kvm->arch.vm_type == KVM_X86_DEFAULT_VM ||
+ vcpu->kvm->arch.vm_type == KVM_X86_SW_PROTECTED_VM) {
+ if (mapping->source)
+ r = -EINVAL;
+ } else if (kvm_x86_ops.pre_mmu_map_page)
+ r = static_call(kvm_x86_pre_mmu_map_page)(vcpu, mapping,
+ &error_code,
+ max_level);
+ else
+ r = -EOPNOTSUPP;
+
+ return r;
+}
+
+static void kvm_post_mmu_map_page(struct kvm_vcpu *vcpu, struct kvm_memory_mapping *mapping)
+{
+ if (vcpu->kvm->arch.vm_type == KVM_X86_DEFAULT_VM ||
+ vcpu->kvm->arch.vm_type == KVM_X86_SW_PROTECTED_VM)
+ return;
+
+ if (kvm_x86_ops.post_mmu_map_page)
+ static_call(kvm_x86_post_mmu_map_page)(vcpu, mapping);
+}
+
int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu,
struct kvm_memory_mapping *mapping)
{
@@ -5842,8 +5872,12 @@ int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu,
else
max_level = PG_LEVEL_4K;

+ r = kvm_pre_mmu_map_page(vcpu, mapping, error_code, &max_level);
+ if (r)
+ return r;
r = kvm_mmu_map_page(vcpu, gfn_to_gpa(mapping->base_gfn), error_code,
max_level, &goal_level);
+ kvm_post_mmu_map_page(vcpu, mapping);
if (r)
return r;

--
2.25.1