From dd232cacbbd407c55bf26299264db0a2c3f0cfcf Mon Sep 17 00:00:00 2001
From: Alexander Potapenko <glider@google.com>
Date: Thu, 11 Sep 2025 18:34:16 +0200
Subject: sys/linux: executor: implement SYZOS_API_WR_DRN on x86

Add a SYZOS call to write to one of the debug registers
(DR0-DR7).
---
 sys/linux/dev_kvm_amd64.txt | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'sys/linux')

diff --git a/sys/linux/dev_kvm_amd64.txt b/sys/linux/dev_kvm_amd64.txt
index 541fcaa02..351f55827 100644
--- a/sys/linux/dev_kvm_amd64.txt
+++ b/sys/linux/dev_kvm_amd64.txt
@@ -69,6 +69,12 @@ syzos_api_wr_crn {
 	arg_value	int64
 }
 
+# Depending on CR4.DE, registers DR4 and DR5 either alias DR6 and DR7, or generate an #UD.
+syzos_api_wr_drn {
+	arg_reg		int64[0:7]
+	arg_value	int64
+}
+
 syzos_api_call$x86 [
 	uexit	syzos_api$x86[0, intptr]
 	code	syzos_api$x86[10, syzos_api_code$x86]
@@ -76,6 +82,7 @@ syzos_api_call$x86 [
 	wrmsr	syzos_api$x86[30, syzos_api_wrmsr]
 	rdmsr	syzos_api$x86[50, syzos_api_rdmsr]
 	wr_crn	syzos_api$x86[70, syzos_api_wr_crn]
+	wr_drn	syzos_api$x86[110, syzos_api_wr_drn]
 ] [varlen]
 
 kvm_text_x86 [
-- 
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