KVM: arm64: selftests: Add helpers to enable debug exceptions

Add helpers to enable breakpoint and watchpoint exceptions.
No functional change intended.
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221020054202.2119018-5-reijiw@google.com

tools/testing/selftests/kvm/aarch64/debug-exceptions.c

@@ -130,10 +130,20 @@ static void enable_os_lock(void)
 	GUEST_ASSERT(read_sysreg(oslsr_el1) & 2);
 }
 
+static void enable_monitor_debug_exceptions(void)
+{
+	uint32_t mdscr;
+
+	asm volatile("msr daifclr, #8");
+
+	mdscr = read_sysreg(mdscr_el1) | MDSCR_KDE | MDSCR_MDE;
+	write_sysreg(mdscr, mdscr_el1);
+	isb();
+}
+
 static void install_wp(uint8_t wpn, uint64_t addr)
 {
 	uint32_t wcr;
-	uint32_t mdscr;
 
 	wcr = DBGWCR_LEN8 | DBGWCR_RD | DBGWCR_WR | DBGWCR_EL1 | DBGWCR_E;
 	write_dbgwcr(wpn, wcr);
@@ -141,28 +151,19 @@ static void install_wp(uint8_t wpn, uint64_t addr)
 
 	isb();
 
-	asm volatile("msr daifclr, #8");
-
-	mdscr = read_sysreg(mdscr_el1) | MDSCR_KDE | MDSCR_MDE;
-	write_sysreg(mdscr, mdscr_el1);
-	isb();
+	enable_monitor_debug_exceptions();
 }
 
 static void install_hw_bp(uint8_t bpn, uint64_t addr)
 {
 	uint32_t bcr;
-	uint32_t mdscr;
 
 	bcr = DBGBCR_LEN8 | DBGBCR_EXEC | DBGBCR_EL1 | DBGBCR_E;
 	write_dbgbcr(bpn, bcr);
 	write_dbgbvr(bpn, addr);
 	isb();
 
-	asm volatile("msr daifclr, #8");
-
-	mdscr = read_sysreg(mdscr_el1) | MDSCR_KDE | MDSCR_MDE;
-	write_sysreg(mdscr, mdscr_el1);
-	isb();
+	enable_monitor_debug_exceptions();
 }
 
 static void install_ss(void)