From:   isaku.yamahata@intel.com
To:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@intel.com, isaku.yamahata@gmail.com,
        Paolo Bonzini <pbonzini@redhat.com>, erdemaktas@google.com,
        Sean Christopherson <seanjc@google.com>,
        Sagi Shahar <sagis@google.com>,
        David Matlack <dmatlack@google.com>,
        Kai Huang <kai.huang@intel.com>,
        Zhi Wang <zhi.wang.linux@gmail.com>
Subject: [PATCH v12 091/106] KVM: TDX: Handle TDX PV map_gpa hypercall
Date:   Mon, 27 Feb 2023 00:23:30 -0800
Message-Id: <7cf93fefc4b2164e35a6e127abcd970c9465f92e.1677484918.git.isaku.yamahata@intel.com>
In-Reply-To: <cover.1677484918.git.isaku.yamahata@intel.com>
References: <cover.1677484918.git.isaku.yamahata@intel.com>
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From: Isaku Yamahata <isaku.yamahata@intel.com>

Wire up TDX PV map_gpa hypercall to the kvm/mmu backend.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
 arch/x86/kvm/vmx/tdx.c | 53 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index f20fcf8325aa..08a4e63e4aea 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1225,6 +1225,57 @@ static int tdx_emulate_wrmsr(struct kvm_vcpu *vcpu)
 	return 1;
 }
 
+static int tdx_map_gpa(struct kvm_vcpu *vcpu)
+{
+	struct kvm *kvm = vcpu->kvm;
+	gpa_t gpa = tdvmcall_a0_read(vcpu);
+	gpa_t size = tdvmcall_a1_read(vcpu);
+	gpa_t end = gpa + size;
+	gfn_t s = gpa_to_gfn(gpa) & ~kvm_gfn_shared_mask(kvm);
+	gfn_t e = gpa_to_gfn(end) & ~kvm_gfn_shared_mask(kvm);
+	int i;
+
+	if (!IS_ALIGNED(gpa, 4096) || !IS_ALIGNED(size, 4096) ||
+	    end < gpa ||
+	    end > kvm_gfn_shared_mask(kvm) << (PAGE_SHIFT + 1) ||
+	    kvm_is_private_gpa(kvm, gpa) != kvm_is_private_gpa(kvm, end)) {
+		tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_INVALID_OPERAND);
+		return 1;
+	}
+
+	/*
+	 * Check how the requested region overlaps with the KVM memory slots.
+	 * For simplicity, require that it must be contained within a memslot or
+	 * it must not overlap with any memslots (MMIO).
+	 */
+	for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
+		struct kvm_memslots *slots = __kvm_memslots(kvm, i);
+		struct kvm_memslot_iter iter;
+
+		kvm_for_each_memslot_in_gfn_range(&iter, slots, s, e) {
+			struct kvm_memory_slot *slot = iter.slot;
+			gfn_t slot_s = slot->base_gfn;
+			gfn_t slot_e = slot->base_gfn + slot->npages;
+
+			/* no overlap */
+			if (e < slot_s || s >= slot_e)
+				continue;
+
+			/* contained in slot */
+			if (slot_s <= s && e <= slot_e) {
+				if (kvm_slot_can_be_private(slot))
+					return tdx_vp_vmcall_to_user(vcpu);
+				continue;
+			}
+
+			break;
+		}
+	}
+
+	tdvmcall_set_return_code(vcpu, TDG_VP_VMCALL_INVALID_OPERAND);
+	return 1;
+}
+
 static int handle_tdvmcall(struct kvm_vcpu *vcpu)
 {
 	if (tdvmcall_exit_type(vcpu))
@@ -1250,6 +1301,8 @@ static int handle_tdvmcall(struct kvm_vcpu *vcpu)
 		 * guest TD doesn't make sense.  No argument check is done.
 		 */
 		return tdx_vp_vmcall_to_user(vcpu);
+	case TDG_VP_VMCALL_MAP_GPA:
+		return tdx_map_gpa(vcpu);
 	default:
 		break;
 	}
-- 
2.25.1