From: Tomasz Jeznach <tjezn...@rivosinc.com>
The HPM (Hardware Performance Monitor) support consists of almost 7
hundred lines that would be put on top of the base riscv-iommu
emulation.
To avoid clogging riscv-iommu.c, add a separated riscv-iommu-hpm file
that will contain HPM specific code.
We'll start by adding riscv_iommu_hpmcycle_read(), a helper that will be
called during the riscv_iommu_mmio_read() callback.
This change will have no effect on the existing emulation since we're
not declaring HPM feature support.
Signed-off-by: Tomasz Jeznach <tjezn...@rivosinc.com>
Signed-off-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>
---
hw/riscv/meson.build | 3 ++-
hw/riscv/riscv-iommu-hpm.c | 54 ++++++++++++++++++++++++++++++++++++++
hw/riscv/riscv-iommu-hpm.h | 27 +++++++++++++++++++
hw/riscv/riscv-iommu.c | 24 ++++++++++++++++-
hw/riscv/riscv-iommu.h | 4 +++
5 files changed, 110 insertions(+), 2 deletions(-)
create mode 100644 hw/riscv/riscv-iommu-hpm.c
create mode 100644 hw/riscv/riscv-iommu-hpm.h
diff --git a/hw/riscv/meson.build b/hw/riscv/meson.build
index 3c7e083aca..c22f3a7216 100644
--- a/hw/riscv/meson.build
+++ b/hw/riscv/meson.build
@@ -10,7 +10,8 @@ riscv_ss.add(when: 'CONFIG_SIFIVE_U', if_true:
files('sifive_u.c'))
riscv_ss.add(when: 'CONFIG_SPIKE', if_true: files('spike.c'))
riscv_ss.add(when: 'CONFIG_MICROCHIP_PFSOC', if_true:
files('microchip_pfsoc.c'))
riscv_ss.add(when: 'CONFIG_ACPI', if_true: files('virt-acpi-build.c'))
-riscv_ss.add(when: 'CONFIG_RISCV_IOMMU', if_true: files('riscv-iommu.c',
'riscv-iommu-pci.c', 'riscv-iommu-sys.c'))
+riscv_ss.add(when: 'CONFIG_RISCV_IOMMU', if_true: files(
+ 'riscv-iommu.c', 'riscv-iommu-pci.c', 'riscv-iommu-sys.c',
'riscv-iommu-hpm.c'))
riscv_ss.add(when: 'CONFIG_MICROBLAZE_V', if_true:
files('microblaze-v-generic.c'))
hw_arch += {'riscv': riscv_ss}
diff --git a/hw/riscv/riscv-iommu-hpm.c b/hw/riscv/riscv-iommu-hpm.c
new file mode 100644
index 0000000000..5833ab8956
--- /dev/null
+++ b/hw/riscv/riscv-iommu-hpm.c
@@ -0,0 +1,54 @@
+/*
+ * RISC-V IOMMU - Hardware Performance Monitor (HPM) helpers
+ *
+ * Copyright (C) 2022-2023 Rivos Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/timer.h"
+#include "cpu_bits.h"
+#include "riscv-iommu-hpm.h"
+#include "riscv-iommu.h"
+#include "riscv-iommu-bits.h"
+#include "trace.h"
+
+/* For now we assume IOMMU HPM frequency to be 1GHz so 1-cycle is of 1-ns. */
+static inline uint64_t get_cycles(void)
+{
+ return qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+}
+
+uint64_t riscv_iommu_hpmcycle_read(RISCVIOMMUState *s)
+{
+ const uint64_t cycle = riscv_iommu_reg_get64(
+ s, RISCV_IOMMU_REG_IOHPMCYCLES);
+ const uint32_t inhibit = riscv_iommu_reg_get32(
+ s, RISCV_IOMMU_REG_IOCOUNTINH);
+ const uint64_t ctr_prev = s->hpmcycle_prev;
+ const uint64_t ctr_val = s->hpmcycle_val;
+
+ if (get_field(inhibit, RISCV_IOMMU_IOCOUNTINH_CY)) {
+ /*
+ * Counter should not increment if inhibit bit is set. We can't really
+ * stop the QEMU_CLOCK_VIRTUAL, so we just return the last updated
+ * counter value to indicate that counter was not incremented.
+ */
+ return (ctr_val & RISCV_IOMMU_IOHPMCYCLES_COUNTER) |
+ (cycle & RISCV_IOMMU_IOHPMCYCLES_OVF);
+ }
+
+ return (ctr_val + get_cycles() - ctr_prev) |
+ (cycle & RISCV_IOMMU_IOHPMCYCLES_OVF);
+}
diff --git a/hw/riscv/riscv-iommu-hpm.h b/hw/riscv/riscv-iommu-hpm.h
new file mode 100644
index 0000000000..231c110ff2
--- /dev/null
+++ b/hw/riscv/riscv-iommu-hpm.h
@@ -0,0 +1,27 @@
+/*
+ * RISC-V IOMMU - Hardware Performance Monitor (HPM) helpers
+ *
+ * Copyright (C) 2022-2023 Rivos Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef HW_RISCV_IOMMU_HPM_H
+#define HW_RISCV_IOMMU_HPM_H
+
+#include "qom/object.h"
+#include "hw/riscv/riscv-iommu.h"
+
+uint64_t riscv_iommu_hpmcycle_read(RISCVIOMMUState *s);
+
+#endif
diff --git a/hw/riscv/riscv-iommu.c b/hw/riscv/riscv-iommu.c
index e9a0775d6e..01df25418c 100644
--- a/hw/riscv/riscv-iommu.c
+++ b/hw/riscv/riscv-iommu.c
@@ -29,6 +29,7 @@
#include "cpu_bits.h"
#include "riscv-iommu.h"
#include "riscv-iommu-bits.h"
+#include "riscv-iommu-hpm.h"
#include "trace.h"
#define LIMIT_CACHE_CTX (1U << 7)
@@ -2052,7 +2053,28 @@ static MemTxResult riscv_iommu_mmio_read(void *opaque,
hwaddr addr,
return MEMTX_ACCESS_ERROR;
}
- ptr = &s->regs_rw[addr];
+ /* Compute cycle register value. */
+ if ((addr & ~7) == RISCV_IOMMU_REG_IOHPMCYCLES) {
+ val = riscv_iommu_hpmcycle_read(s);
+ ptr = (uint8_t *)&val + (addr & 7);
+ } else if ((addr & ~3) == RISCV_IOMMU_REG_IOCOUNTOVF) {
+ /*
+ * Software can read RISCV_IOMMU_REG_IOCOUNTOVF before timer
+ * callback completes. In which case CY_OF bit in
+ * RISCV_IOMMU_IOHPMCYCLES_OVF would be 0. Here we take the
+ * CY_OF bit state from RISCV_IOMMU_REG_IOHPMCYCLES register as
+ * it's not dependent over the timer callback and is computed
+ * from cycle overflow.
+ */
+ val = ldq_le_p(&s->regs_rw[addr]);
+ val |= (riscv_iommu_hpmcycle_read(s) & RISCV_IOMMU_IOHPMCYCLES_OVF)
+ ? RISCV_IOMMU_IOCOUNTOVF_CY
+ : 0;
+ ptr = (uint8_t *)&val + (addr & 3);
+ } else {
+ ptr = &s->regs_rw[addr];
+ }
+
val = ldn_le_p(ptr, size);
*data = val;
diff --git a/hw/riscv/riscv-iommu.h b/hw/riscv/riscv-iommu.h
index 2de0cdfc56..380f7e81d1 100644
--- a/hw/riscv/riscv-iommu.h
+++ b/hw/riscv/riscv-iommu.h
@@ -86,6 +86,10 @@ struct RISCVIOMMUState {
QLIST_ENTRY(RISCVIOMMUState) iommus;
QLIST_HEAD(, RISCVIOMMUSpace) spaces;
+
+ /* HPM cycle counter */
+ uint64_t hpmcycle_val; /* Current value of cycle register */
+ uint64_t hpmcycle_prev; /* Saved value of QEMU_CLOCK_VIRTUAL clock */
};
void riscv_iommu_pci_setup_iommu(RISCVIOMMUState *iommu, PCIBus *bus,
--
2.47.1
