git: 231eee17d290 - main - vmm: enable software breakpoints for AMD CPUs

The branch main has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=231eee17d2905682014b71d1f01719003b13bd91

commit 231eee17d2905682014b71d1f01719003b13bd91
Author:     Bojan Novković <bojan.novkovic@fer.hr>
AuthorDate: 2023-12-07 22:46:31 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2023-12-07 23:10:56 +0000

    vmm: enable software breakpoints for AMD CPUs
    
    This patch adds support for software breakpoint vmexits on AMD SVM.
    It implements the VM_CAP_BPT_EXIT used to enable software breakpoints.
    When enabled, breakpoint vmexits are passed to userspace where they
    are handled by the GDB stub.
    
    Reviewed by:    jhb
    Sponsored by:   Google, Inc. (GSoC 2022)
    Differential Revision:  https://reviews.freebsd.org/D42295
---
 sys/amd64/vmm/amd/svm.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/sys/amd64/vmm/amd/svm.c b/sys/amd64/vmm/amd/svm.c
index a502632f6ed6..ec0cde31aaad 100644
--- a/sys/amd64/vmm/amd/svm.c
+++ b/sys/amd64/vmm/amd/svm.c
@@ -1421,6 +1421,12 @@ svm_vmexit(struct svm_softc *svm_sc, struct svm_vcpu *vcpu,
 			break;
 
 		case IDT_BP:
+			vmexit->exitcode = VM_EXITCODE_BPT;
+			vmexit->u.bpt.inst_length = vmexit->inst_length;
+			vmexit->inst_length = 0;
+
+			reflect = 0;
+			break;
 		case IDT_OF:
 		case IDT_BR:
 			/*
@@ -2333,6 +2339,9 @@ svm_setcap(void *vcpui, int type, int val)
 		if (val == 0)
 			error = EINVAL;
 		break;
+	case VM_CAP_BPT_EXIT:
+		svm_set_intercept(vcpu, VMCB_EXC_INTCPT, BIT(IDT_BP), val);
+		break;
 	case VM_CAP_IPI_EXIT:
 		vlapic = vm_lapic(vcpu->vcpu);
 		vlapic->ipi_exit = val;
@@ -2366,6 +2375,9 @@ svm_getcap(void *vcpui, int type, int *retval)
 	case VM_CAP_UNRESTRICTED_GUEST:
 		*retval = 1;	/* unrestricted guest is always enabled */
 		break;
+	case VM_CAP_BPT_EXIT:
+		*retval = svm_get_intercept(vcpu, VMCB_EXC_INTCPT, BIT(IDT_BP));
+		break;
 	case VM_CAP_IPI_EXIT:
 		vlapic = vm_lapic(vcpu->vcpu);
 		*retval = vlapic->ipi_exit;