linux-kernel - [PATCH v2 06/10] KVM: x86: Implement kvm_arch_vcpu_map

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Message-ID: <7138a3bc00ea8d3cbe0e59df15f8c22027005b59.1712785629.git.isaku.yamahata@intel.com>
Date: Wed, 10 Apr 2024 15:07:32 -0700
From: isaku.yamahata@...el.com
To: kvm@...r.kernel.org
Cc: isaku.yamahata@...el.com,
	isaku.yamahata@...il.com,
	linux-kernel@...r.kernel.org,
	Sean Christopherson <seanjc@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Michael Roth <michael.roth@....com>,
	David Matlack <dmatlack@...gle.com>,
	Federico Parola <federico.parola@...ito.it>,
	Kai Huang <kai.huang@...el.com>
Subject: [PATCH v2 06/10] KVM: x86: Implement kvm_arch_vcpu_map_memory()

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

Wire KVM_MAP_MEMORY ioctl to kvm_mmu_map_tdp_page() to populate guest
memory.  When KVM_CREATE_VCPU creates vCPU, it initializes the x86
KVM MMU part by kvm_mmu_create() and kvm_init_mmu().  vCPU is ready to
invoke the KVM page fault handler.

Signed-off-by: Isaku Yamahata <isaku.yamahata@...el.com>
---
v2:
- Catch up the change of struct kvm_memory_mapping. (Sean)
- Removed mapping level check. Push it down into vendor code. (David, Sean)
- Rename goal_level to level. (Sean)
- Drop kvm_arch_pre_vcpu_map_memory(), directly call kvm_mmu_reload().
  (David, Sean)
- Fixed the update of mapping.
---
 arch/x86/kvm/x86.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2d2619d3eee4..2c765de3531e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4713,6 +4713,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_VM_DISABLE_NX_HUGE_PAGES:
 	case KVM_CAP_IRQFD_RESAMPLE:
 	case KVM_CAP_MEMORY_FAULT_INFO:
+	case KVM_CAP_MAP_MEMORY:
 		r = 1;
 		break;
 	case KVM_CAP_EXIT_HYPERCALL:
@@ -5867,6 +5868,35 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
 	}
 }
 
+int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu,
+			     struct kvm_memory_mapping *mapping)
+{
+	u64 end, error_code = 0;
+	u8 level = PG_LEVEL_4K;
+	int r;
+
+	/*
+	 * Shadow paging uses GVA for kvm page fault.  The first implementation
+	 * supports GPA only to avoid confusion.
+	 */
+	if (!tdp_enabled)
+		return -EOPNOTSUPP;
+
+	/* reload is optimized for repeated call. */
+	kvm_mmu_reload(vcpu);
+
+	r = kvm_tdp_map_page(vcpu, mapping->base_address, error_code, &level);
+	if (r)
+		return r;
+
+	/* mapping->base_address is not necessarily aligned to level-hugepage. */
+	end = (mapping->base_address & KVM_HPAGE_MASK(level)) +
+		KVM_HPAGE_SIZE(level);
+	mapping->size -= end - mapping->base_address;
+	mapping->base_address = end;
+	return r;
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp,
 			 unsigned int ioctl, unsigned long arg)
 {
-- 
2.43.2