[Qemu-devel] [RFC PATCH v3 12/18] spapr_rtas: Add Dynamic DMA windows (DDW) RTAS calls support

[Alexey Kardashevskiy <aik@ozlabs.ru>]

NO RESET

This adds support for Dynamic DMA Windows (DDW) option defined by
the SPAPR specification which allows to have additional DMA window(s)
which can support page sizes other than 4K.

The existing implementation of DDW in the guest tries to create one huge
DMA window with 64K or 16MB pages and map the entire guest RAM to. If it
succeeds, the guest switches to dma_direct_ops and never calls
TCE hypercalls (H_PUT_TCE,...) again. This enables VFIO devices to use
the entire RAM and not waste time on map/unmap.

This adds 4 RTAS handlers:
* ibm,query-pe-dma-window
* ibm,create-pe-dma-window
* ibm,remove-pe-dma-window
* ibm,reset-pe-dma-window
These are registered from type_init() callback.

These RTAS handlers are implemented in a separate file to avoid polluting
spapr_iommu.c with PHB.

Since no PHB class implements new callback in this patch, no functional
change is expected.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v2:
* double loop squashed to spapr_iommu_fixmask() helper
* added @ddw_num counter to PHB, it is used to generate LIOBN for new
window; it is reset on ddw-reset event
* added ULL to constants used in shift operations
* rtas_ibm_reset_pe_dma_window() and rtas_ibm_remove_pe_dma_window()
do not remove windows anymore, the PHB callback has to as it will reuse
the same code in case of guest reboot as well
---
 hw/ppc/Makefile.objs    |   3 +
 hw/ppc/spapr_rtas_ddw.c | 234 ++++++++++++++++++++++++++++++++++++++++++++++++
 trace-events            |   3 +
 3 files changed, 240 insertions(+)
 create mode 100644 hw/ppc/spapr_rtas_ddw.c

diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
index edd44d0..9773294 100644
--- a/hw/ppc/Makefile.objs
+++ b/hw/ppc/Makefile.objs
@@ -7,6 +7,9 @@ obj-$(CONFIG_PSERIES) += spapr_pci.o
 ifeq ($(CONFIG_PCI)$(CONFIG_PSERIES)$(CONFIG_LINUX), yyy)
 obj-y += spapr_pci_vfio.o
 endif
+ifeq ($(CONFIG_PCI)$(CONFIG_PSERIES), yy)
+obj-y += spapr_rtas_ddw.o
+endif
 # PowerPC 4xx boards
 obj-y += ppc405_boards.o ppc4xx_devs.o ppc405_uc.o ppc440_bamboo.o
 obj-y += ppc4xx_pci.o
diff --git a/hw/ppc/spapr_rtas_ddw.c b/hw/ppc/spapr_rtas_ddw.c
new file mode 100644
index 0000000..9ed15dc
--- /dev/null
+++ b/hw/ppc/spapr_rtas_ddw.c
@@ -0,0 +1,234 @@
+/*
+ * QEMU sPAPR Dynamic DMA windows support
+ *
+ * Copyright (c) 2014 Alexey Kardashevskiy, IBM Corporation.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License,
+ *  or (at your option) any later version.
+ *
+ *  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 "hw/ppc/spapr.h"
+#include "hw/pci-host/spapr.h"
+#include "trace.h"
+
+static uint32_t spapr_iommu_fixmask(struct ppc_one_seg_page_size *sps,
+                                    uint32_t query_mask)
+{
+    int i, j;
+    uint32_t mask = 0;
+    const struct { int shift; uint32_t mask; } masks[] = {
+        { 12, DDW_PGSIZE_4K },
+        { 16, DDW_PGSIZE_64K },
+        { 24, DDW_PGSIZE_16M },
+        { 25, DDW_PGSIZE_32M },
+        { 26, DDW_PGSIZE_64M },
+        { 27, DDW_PGSIZE_128M },
+        { 28, DDW_PGSIZE_256M },
+        { 34, DDW_PGSIZE_16G },
+    };
+
+    for (i = 0; i < PPC_PAGE_SIZES_MAX_SZ; i++) {
+        for (j = 0; j < ARRAY_SIZE(masks); ++j) {
+            if ((sps[i].page_shift == masks[j].shift) &&
+                    (query_mask & masks[j].mask)) {
+                mask |= masks[j].mask;
+            }
+        }
+    }
+
+    return mask;
+}
+
+static void rtas_ibm_query_pe_dma_window(PowerPCCPU *cpu,
+                                         sPAPREnvironment *spapr,
+                                         uint32_t token, uint32_t nargs,
+                                         target_ulong args,
+                                         uint32_t nret, target_ulong rets)
+{
+    CPUPPCState *env = &cpu->env;
+    sPAPRPHBState *sphb;
+    sPAPRPHBClass *spc;
+    uint64_t buid;
+    uint32_t addr, pgmask = 0;
+    uint32_t windows_available = 0, page_size_mask = 0;
+    long ret;
+
+    if ((nargs != 3) || (nret != 5)) {
+        goto param_error_exit;
+    }
+
+    buid = ((uint64_t)rtas_ld(args, 1) << 32) | rtas_ld(args, 2);
+    addr = rtas_ld(args, 0);
+    sphb = spapr_pci_find_phb(spapr, buid);
+    if (!sphb) {
+        goto param_error_exit;
+    }
+
+    spc = SPAPR_PCI_HOST_BRIDGE_GET_CLASS(sphb);
+    if (!spc->ddw_query) {
+        goto hw_error_exit;
+    }
+
+    ret = spc->ddw_query(sphb, &windows_available, &page_size_mask);
+    trace_spapr_iommu_ddw_query(buid, addr, windows_available,
+                                page_size_mask, pgmask, ret);
+    if (ret) {
+        goto hw_error_exit;
+    }
+
+    /* Work out supported page masks */
+    pgmask = spapr_iommu_fixmask(env->sps.sps, page_size_mask);
+
+    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+    rtas_st(rets, 1, windows_available);
+
+    /*
+     * This is "Largest contiguous block of TCEs allocated specifically
+     * for (that is, are reserved for) this PE".
+     * Return the maximum number as all RAM was in 4K pages.
+     */
+    rtas_st(rets, 2, ram_size >> SPAPR_TCE_PAGE_SHIFT);
+    rtas_st(rets, 3, pgmask);
+    rtas_st(rets, 4, pgmask); /* DMA migration mask */
+    return;
+
+hw_error_exit:
+    rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
+    return;
+
+param_error_exit:
+    rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+}
+
+static void rtas_ibm_create_pe_dma_window(PowerPCCPU *cpu,
+                                          sPAPREnvironment *spapr,
+                                          uint32_t token, uint32_t nargs,
+                                          target_ulong args,
+                                          uint32_t nret, target_ulong rets)
+{
+    sPAPRPHBState *sphb;
+    sPAPRPHBClass *spc;
+    sPAPRTCETable *tcet = NULL;
+    uint32_t addr, page_shift, window_shift, liobn;
+    uint64_t buid;
+    long ret;
+
+    if ((nargs != 5) || (nret != 4)) {
+        goto param_error_exit;
+    }
+
+    buid = ((uint64_t)rtas_ld(args, 1) << 32) | rtas_ld(args, 2);
+    addr = rtas_ld(args, 0);
+    sphb = spapr_pci_find_phb(spapr, buid);
+    if (!sphb) {
+        goto param_error_exit;
+    }
+
+    spc = SPAPR_PCI_HOST_BRIDGE_GET_CLASS(sphb);
+    if (!spc->ddw_create) {
+        goto hw_error_exit;
+    }
+
+    page_shift = rtas_ld(args, 3);
+    window_shift = rtas_ld(args, 4);
+    /* Default 32bit window#0 is always there so +1 */
+    liobn = SPAPR_PCI_LIOBN(sphb->index, sphb->windows_num);
+
+    ret = spc->ddw_create(sphb, page_shift, window_shift, liobn, &tcet);
+    trace_spapr_iommu_ddw_create(buid, addr, 1ULL << page_shift,
+                                 1ULL << window_shift,
+                                 tcet ? tcet->bus_offset : 0xbaadf00d,
+                                 liobn, ret);
+    if (ret || !tcet) {
+        goto hw_error_exit;
+    }
+
+    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+    rtas_st(rets, 1, liobn);
+    rtas_st(rets, 2, tcet->bus_offset >> 32);
+    rtas_st(rets, 3, tcet->bus_offset & ((uint32_t) -1));
+
+    object_unref(OBJECT(tcet));
+    return;
+
+hw_error_exit:
+    rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
+    return;
+
+param_error_exit:
+    rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+}
+
+static void rtas_ibm_remove_pe_dma_window(PowerPCCPU *cpu,
+                                          sPAPREnvironment *spapr,
+                                          uint32_t token, uint32_t nargs,
+                                          target_ulong args,
+                                          uint32_t nret, target_ulong rets)
+{
+    sPAPRPHBState *sphb;
+    sPAPRPHBClass *spc;
+    sPAPRTCETable *tcet;
+    uint32_t liobn;
+    long ret;
+
+    if ((nargs != 1) || (nret != 1)) {
+        goto param_error_exit;
+    }
+
+    liobn = rtas_ld(args, 0);
+    tcet = spapr_tce_find_by_liobn(liobn);
+    if (!tcet) {
+        goto param_error_exit;
+    }
+
+    sphb = SPAPR_PCI_HOST_BRIDGE(OBJECT(tcet)->parent);
+    if (!sphb) {
+        goto param_error_exit;
+    }
+
+    spc = SPAPR_PCI_HOST_BRIDGE_GET_CLASS(sphb);
+    if (!spc->ddw_remove) {
+        goto hw_error_exit;
+    }
+
+    ret = spc->ddw_remove(sphb, tcet);
+    trace_spapr_iommu_ddw_remove(liobn, ret);
+    if (ret) {
+        goto hw_error_exit;
+    }
+
+    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+    return;
+
+hw_error_exit:
+    rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
+    return;
+
+param_error_exit:
+    rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+}
+
+static void spapr_rtas_ddw_init(void)
+{
+    spapr_rtas_register(RTAS_IBM_QUERY_PE_DMA_WINDOW,
+                        "ibm,query-pe-dma-window",
+                        rtas_ibm_query_pe_dma_window);
+    spapr_rtas_register(RTAS_IBM_CREATE_PE_DMA_WINDOW,
+                        "ibm,create-pe-dma-window",
+                        rtas_ibm_create_pe_dma_window);
+    spapr_rtas_register(RTAS_IBM_REMOVE_PE_DMA_WINDOW,
+                        "ibm,remove-pe-dma-window",
+                        rtas_ibm_remove_pe_dma_window);
+}
+
+type_init(spapr_rtas_ddw_init)
diff --git a/trace-events b/trace-events
index 81bc915..0d8de94 100644
--- a/trace-events
+++ b/trace-events
@@ -1218,6 +1218,9 @@ spapr_iommu_indirect(uint64_t liobn, uint64_t ioba, uint64_t tce, uint64_t iobaN
 spapr_iommu_stuff(uint64_t liobn, uint64_t ioba, uint64_t tce_value, uint64_t npages, uint64_t ret) "liobn=%"PRIx64" ioba=0x%"PRIx64" tcevalue=0x%"PRIx64" npages=%"PRId64" ret=%"PRId64
 spapr_iommu_xlate(uint64_t liobn, uint64_t ioba, uint64_t tce, unsigned perm, unsigned pgsize) "liobn=%"PRIx64" 0x%"PRIx64" -> 0x%"PRIx64" perm=%u mask=%x"
 spapr_iommu_new_table(uint64_t liobn, void *tcet, void *table, int fd) "liobn=%"PRIx64" tcet=%p table=%p fd=%d"
+spapr_iommu_ddw_query(uint64_t buid, uint32_t cfgaddr, uint32_t wa, uint32_t pgz, uint32_t pgz_fixed, long ret) "buid=%"PRIx64" addr=%"PRIx32", %u windows available, sizes %"PRIx32", fixed %"PRIx32", ret = %ld"
+spapr_iommu_ddw_create(uint64_t buid, uint32_t cfgaddr, unsigned long long pg_size, unsigned long long req_size, uint64_t start, uint32_t liobn, long ret) "buid=%"PRIx64" addr=%"PRIx32", page size=0x%llx, requested=0x%llx, start addr=%"PRIx64", liobn=%"PRIx32", ret = %ld"
+spapr_iommu_ddw_remove(uint32_t liobn, long ret) "liobn=%"PRIx32", ret = %ld"
 
 # hw/ppc/ppc.c
 ppc_tb_adjust(uint64_t offs1, uint64_t offs2, int64_t diff, int64_t seconds) "adjusted from 0x%"PRIx64" to 0x%"PRIx64", diff %"PRId64" (%"PRId64"s)"
-- 
2.0.0