git: 9f85826c88ea - stable/15 - arm64/vmm: Handle debug exits

The branch stable/15 has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=9f85826c88ea1c5f07c2d3b9fbc8458f91c4f097

commit 9f85826c88ea1c5f07c2d3b9fbc8458f91c4f097
Author:     Andrew Turner <andrew@FreeBSD.org>
AuthorDate: 2025-10-07 08:26:00 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2025-10-09 16:31:50 +0000

    arm64/vmm: Handle debug exits
    
    This is enough to boot FreeBSD again.
    
    PR:             290044
    Reported by:    Siva Mahadevan <me@svmhdvn.name>
    Sponsored by:   Arm Ltd
    Differential Revision:  https://reviews.freebsd.org/D52931
    
    (cherry picked from commit 534aec00976c18c4c4b485b2fade9d5f33de89c8)
---
 sys/arm64/vmm/arm64.h |  1 +
 sys/arm64/vmm/vmm.c   | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/sys/arm64/vmm/arm64.h b/sys/arm64/vmm/arm64.h
index 6a4af47ac60a..10261c6a6499 100644
--- a/sys/arm64/vmm/arm64.h
+++ b/sys/arm64/vmm/arm64.h
@@ -119,6 +119,7 @@ struct hypctx {
 	struct vgic_v3_regs	vgic_v3_regs;
 	struct vgic_v3_cpu	*vgic_cpu;
 	bool			has_exception;
+	bool			dbg_oslock;
 };
 
 struct hyp {
diff --git a/sys/arm64/vmm/vmm.c b/sys/arm64/vmm/vmm.c
index 1dcefa1489e9..a551a2807183 100644
--- a/sys/arm64/vmm/vmm.c
+++ b/sys/arm64/vmm/vmm.c
@@ -651,6 +651,33 @@ vmm_reg_wi(struct vcpu *vcpu, uint64_t wval, void *arg)
 	return (0);
 }
 
+static int
+vmm_write_oslar_el1(struct vcpu *vcpu, uint64_t wval, void *arg)
+{
+	struct hypctx *hypctx;
+
+	hypctx = vcpu_get_cookie(vcpu);
+	/* All other fields are RES0 & we don't do anything with this */
+	/* TODO: Disable access to other debug state when locked */
+	hypctx->dbg_oslock = (wval & OSLAR_OSLK) == OSLAR_OSLK;
+	return (0);
+}
+
+static int
+vmm_read_oslsr_el1(struct vcpu *vcpu, uint64_t *rval, void *arg)
+{
+	struct hypctx *hypctx;
+	uint64_t val;
+
+	hypctx = vcpu_get_cookie(vcpu);
+	val = OSLSR_OSLM_1;
+	if (hypctx->dbg_oslock)
+		val |= OSLSR_OSLK;
+	*rval = val;
+
+	return (0);
+}
+
 static const struct vmm_special_reg vmm_special_regs[] = {
 #define	SPECIAL_REG(_reg, _read, _write)				\
 	{								\
@@ -707,6 +734,13 @@ static const struct vmm_special_reg vmm_special_regs[] = {
 	SPECIAL_REG(CNTP_TVAL_EL0, vtimer_phys_tval_read,
 	    vtimer_phys_tval_write),
 	SPECIAL_REG(CNTPCT_EL0, vtimer_phys_cnt_read, vtimer_phys_cnt_write),
+
+	/* Debug registers */
+	SPECIAL_REG(DBGPRCR_EL1, vmm_reg_raz, vmm_reg_wi),
+	SPECIAL_REG(OSDLR_EL1, vmm_reg_raz, vmm_reg_wi),
+	/* TODO: Exceptions on invalid access */
+	SPECIAL_REG(OSLAR_EL1, vmm_reg_raz, vmm_write_oslar_el1),
+	SPECIAL_REG(OSLSR_EL1, vmm_read_oslsr_el1, vmm_reg_wi),
 #undef SPECIAL_REG
 };