KVM: arm64: selftests: Add basic support for arch_timers

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>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211007233439.1826892-7-rananta@google.com

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 (file)
index 0000000..cb7c03d
--- /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 */