[PATCH v5 06/14] KVM: arm64: selftests: Add basic support for arch_timers

Raghavendra Rao Ananta
2021-09-13T20:50:36Z

Add a minimalistic library support to access the virtual timers,
that can be used for simple timing functionalities, such as
introducing delays in the guest.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
.../kvm/include/aarch64/arch_timer.h | 142 ++++++++++++++++++
1 file changed, 142 insertions(+)
create mode 100644 tools/testing/selftests/kvm/include/aarch64/arch_timer.h

diff --git a/tools/testing/selftests/kvm/include/aarch64/arch_timer.h b/tools/testing/selftests/kvm/include/aarch64/arch_timer.h
new file mode 100644
index 000000000000..cb7c03de3a21
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/aarch64/arch_timer.h
@@ -0,0 +1,142 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * ARM Generic Timer specific interface
+ */
+
+#ifndef SELFTEST_KVM_ARCH_TIMER_H
+#define SELFTEST_KVM_ARCH_TIMER_H
+
+#include "processor.h"
+
+enum arch_timer {
+ VIRTUAL,
+ PHYSICAL,
+};
+
+#define CTL_ENABLE (1 << 0)
+#define CTL_IMASK (1 << 1)
+#define CTL_ISTATUS (1 << 2)
+
+#define msec_to_cycles(msec) \
+ (timer_get_cntfrq() * (uint64_t)(msec) / 1000)
+
+#define usec_to_cycles(usec) \
+ (timer_get_cntfrq() * (uint64_t)(usec) / 1000000)
+
+#define cycles_to_usec(cycles) \
+ ((uint64_t)(cycles) * 1000000 / timer_get_cntfrq())
+
+static inline uint32_t timer_get_cntfrq(void)
+{
+ return read_sysreg(cntfrq_el0);
+}
+
+static inline uint64_t timer_get_cntct(enum arch_timer timer)
+{
+ isb();
+
+ switch (timer) {
+ case VIRTUAL:
+ return read_sysreg(cntvct_el0);
+ case PHYSICAL:
+ return read_sysreg(cntpct_el0);
+ default:
+ GUEST_ASSERT_1(0, timer);
+ }
+
+ /* We should not reach here */
+ return 0;
+}
+
+static inline void timer_set_cval(enum arch_timer timer, uint64_t cval)
+{
+ switch (timer) {
+ case VIRTUAL:
+ write_sysreg(cval, cntv_cval_el0);
+ break;
+ case PHYSICAL:
+ write_sysreg(cval, cntp_cval_el0);
+ break;
+ default:
+ GUEST_ASSERT_1(0, timer);
+ }
+
+ isb();
+}
+
+static inline uint64_t timer_get_cval(enum arch_timer timer)
+{
+ switch (timer) {
+ case VIRTUAL:
+ return read_sysreg(cntv_cval_el0);
+ case PHYSICAL:
+ return read_sysreg(cntp_cval_el0);
+ default:
+ GUEST_ASSERT_1(0, timer);
+ }
+
+ /* We should not reach here */
+ return 0;
+}
+
+static inline void timer_set_tval(enum arch_timer timer, uint32_t tval)
+{
+ switch (timer) {
+ case VIRTUAL:
+ write_sysreg(tval, cntv_tval_el0);
+ break;
+ case PHYSICAL:
+ write_sysreg(tval, cntp_tval_el0);
+ break;
+ default:
+ GUEST_ASSERT_1(0, timer);
+ }
+
+ isb();
+}
+
+static inline void timer_set_ctl(enum arch_timer timer, uint32_t ctl)
+{
+ switch (timer) {
+ case VIRTUAL:
+ write_sysreg(ctl, cntv_ctl_el0);
+ break;
+ case PHYSICAL:
+ write_sysreg(ctl, cntp_ctl_el0);
+ break;
+ default:
+ GUEST_ASSERT_1(0, timer);
+ }
+
+ isb();
+}
+
+static inline uint32_t timer_get_ctl(enum arch_timer timer)
+{
+ switch (timer) {
+ case VIRTUAL:
+ return read_sysreg(cntv_ctl_el0);
+ case PHYSICAL:
+ return read_sysreg(cntp_ctl_el0);
+ default:
+ GUEST_ASSERT_1(0, timer);
+ }
+
+ /* We should not reach here */
+ return 0;
+}
+
+static inline void timer_set_next_cval_ms(enum arch_timer timer, uint32_t msec)
+{
+ uint64_t now_ct = timer_get_cntct(timer);
+ uint64_t next_ct = now_ct + msec_to_cycles(msec);
+
+ timer_set_cval(timer, next_ct);
+}
+
+static inline void timer_set_next_tval_ms(enum arch_timer timer, uint32_t msec)
+{
+ timer_set_tval(timer, msec_to_cycles(msec));
+}
+
+#endif /* SELFTEST_KVM_ARCH_TIMER_H */
--
2.33.0.309.g3052b89438-goog