feat: cpuid-query patch

Author: ShivanshVij

patches/cpuid-query.patch

@@ -0,0 +1,88 @@
+From: Shivansh Vij <[email protected]>
+Subject: feat: implement CPUID query
+---
+diff --git a/arch/x86/kvm/pvm/pvm.c b/arch/x86/kvm/pvm/pvm.c
+index 2bc9a7b07..b9caace4f 100644
+--- a/arch/x86/kvm/pvm/pvm.c
++++ b/arch/x86/kvm/pvm/pvm.c
+@@ -2193,6 +2193,19 @@ static int handle_exit_breakpoint(struct kvm_vcpu *vcpu)
+ 	return 1;
+ }
+ 
++static void handle_cpuid(struct kvm_vcpu *vcpu)
++{
++	u32 eax, ebx, ecx, edx;
++
++	eax = kvm_rax_read(vcpu);
++	ecx = kvm_rcx_read(vcpu);
++	kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, false);
++	kvm_rax_write(vcpu, eax);
++	kvm_rbx_write(vcpu, ebx);
++	kvm_rcx_write(vcpu, ecx);
++	kvm_rdx_write(vcpu, edx);
++}
++
+ static bool handle_synthetic_instruction_pvm_cpuid(struct kvm_vcpu *vcpu)
+ {
+ 	/* invlpg 0xffffffffff4d5650; cpuid; */
+@@ -2203,19 +2216,10 @@ static bool handle_synthetic_instruction_pvm_cpuid(struct kvm_vcpu *vcpu)
+ 	if (kvm_read_guest_virt(vcpu, kvm_get_linear_rip(vcpu),
+ 				insns, sizeof(insns), &e) == 0 &&
+ 	    memcmp(insns, pvm_synthetic_cpuid_insns, sizeof(insns)) == 0) {
+-		u32 eax, ebx, ecx, edx;
+-
+ 		if (unlikely(pvm_guest_allowed_va(vcpu, PVM_SYNTHETIC_CPUID_ADDRESS)))
+ 			kvm_mmu_invlpg(vcpu, PVM_SYNTHETIC_CPUID_ADDRESS);
+ 
+-		eax = kvm_rax_read(vcpu);
+-		ecx = kvm_rcx_read(vcpu);
+-		kvm_cpuid(vcpu, &eax, &ebx, &ecx, &edx, false);
+-		kvm_rax_write(vcpu, eax);
+-		kvm_rbx_write(vcpu, ebx);
+-		kvm_rcx_write(vcpu, ecx);
+-		kvm_rdx_write(vcpu, edx);
+-
++		handle_cpuid(vcpu);
+ 		kvm_rip_write(vcpu, kvm_rip_read(vcpu) + sizeof(insns));
+ 		return true;
+ 	}
+@@ -2223,6 +2227,28 @@ static bool handle_synthetic_instruction_pvm_cpuid(struct kvm_vcpu *vcpu)
+ 	return false;
+ }
+ 
++/*
++ * Handle the guest initiated #VE.
++ *
++ * Only EXIT_REASON_CPUID is allowed for now, see virt_exception_user()
++ * in arch/x86/coco/tdx/tdx.c.
++ */
++static void handle_exit_virtual_exception(struct kvm_vcpu *vcpu)
++{
++	struct vcpu_pvm *pvm = to_pvm(vcpu);
++
++	switch (pvm->exit_ve.exit_reason) {
++	case EXIT_REASON_CPUID:
++		handle_cpuid(vcpu);
++		kvm_rip_write(vcpu, kvm_rip_read(vcpu) + pvm->exit_ve.instr_len);
++		break;
++	default:
++		pr_warn("Unexpected #VE: %lld\n", pvm->exit_ve.exit_reason);
++		kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
++		break;
++	}
++}
++
+ static int handle_exit_exception(struct kvm_vcpu *vcpu)
+ {
+ 	struct vcpu_pvm *pvm = to_pvm(vcpu);
+@@ -2296,8 +2322,8 @@ static int handle_exit_exception(struct kvm_vcpu *vcpu)
+ 		// NMI is handled by pvm_vcpu_run_noinstr().
+ 		return 1;
+ 	case VE_VECTOR:
+-		// TODO: tdx_handle_virt_exception(regs, &pvm->exit_ve); break;
+-		goto unknown_exit_reason;
++		handle_exit_virtual_exception(vcpu);
++		return 1;
+ 	case X86_TRAP_VC:
+ 		// TODO: handle the second part for #VC.
+ 		goto unknown_exit_reason;