Re: [Qemu-devel] [PATCH v4 12/18] spapr_rtas: Add Dynamic DMA windows (DDW) RTAS handlers

[David Gibson]

On Thu, Jan 29, 2015 at 08:27:24PM +1100, Alexey Kardashevskiy wrote:
> 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 later.
> 
> 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.
> 
> Signed-off-by: Alexey Kardashevskiy <address@hidden>
> ---
> Changes:
> v3:
> * added ibm,reset-pe-dma-window
> 
> 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 | 297 
> ++++++++++++++++++++++++++++++++++++++++++++++++
>  trace-events            |   4 +
>  3 files changed, 304 insertions(+)
>  create mode 100644 hw/ppc/spapr_rtas_ddw.c
> 
> diff --git a/hw/ppc/Makefile.objs b/hw/ppc/Makefile.objs
> index 19d9920..d7fe4fb 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..af70601
> --- /dev/null
> +++ b/hw/ppc/spapr_rtas_ddw.c
> @@ -0,0 +1,297 @@
> +/*
> + * 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)

This function could do with a comment describing what it's for.  Every
version of this series I've looked at I've forgotten and had to figure
it out again.

> +{
> +    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 avail, addr, pgmask = 0;
> +    uint32_t windows_supported = 0, page_size_mask = 0, dma32_window_size = 
> 0;
> +    uint64_t dma64_window_size = 0;
> +    unsigned current;
> +    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 || !sphb->ddw_enabled) {
> +        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_supported, &page_size_mask,
> +                         &dma32_window_size, &dma64_window_size);
> +    trace_spapr_iommu_ddw_query(buid, addr, windows_supported,
> +                                page_size_mask, pgmask, ret);
> +    if (ret) {
> +        goto hw_error_exit;
> +    }
> +
> +    current = spapr_phb_get_win_num(sphb);
> +    avail = (windows_supported > current) ? (windows_supported - current) : 
> 0;
> +
> +    /* 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, avail);
> +
> +    /*
> +     * 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, dma64_window_size >> SPAPR_TCE_PAGE_SHIFT);
> +    rtas_st(rets, 3, pgmask);
> +    rtas_st(rets, 4, 0); /* DMA migration mask, not supported */
> +    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;
> +    uint32_t windows_supported = 0, page_size_mask = 0, dma32_window_size = 
> 0;
> +    uint64_t dma64_window_size = 0;
> +
> +    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 || !sphb->ddw_enabled) {
> +        goto param_error_exit;
> +    }
> +
> +    spc = SPAPR_PCI_HOST_BRIDGE_GET_CLASS(sphb);
> +    if (!spc->ddw_create || !spc->ddw_query) {
> +        goto hw_error_exit;
> +    }
> +
> +    ret = spc->ddw_query(sphb, &windows_supported, &page_size_mask,
> +                         &dma32_window_size, &dma64_window_size);
> +    if (ret || (spapr_phb_get_win_num(sphb) >= windows_supported)) {
> +        goto hw_error_exit;

Is RTAS_OUT_HW_ERROR really the right thing for the case of having
allocated all the available windows?

> +    }
> +
> +    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, spapr_phb_get_win_num(sphb));
> +
> +    ret = spc->ddw_create(sphb, liobn, page_shift, window_shift, &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 || !sphb->ddw_enabled) {
> +        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 rtas_ibm_reset_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;
> +    uint64_t buid;
> +    uint32_t addr;
> +    long ret;
> +
> +    if ((nargs != 3) || (nret != 1)) {
> +        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 || !sphb->ddw_enabled) {
> +        goto param_error_exit;
> +    }
> +
> +    spc = SPAPR_PCI_HOST_BRIDGE_GET_CLASS(sphb);
> +    if (!spc->ddw_reset) {
> +        goto hw_error_exit;
> +    }
> +
> +    ret = spc->ddw_reset(sphb);
> +    trace_spapr_iommu_ddw_reset(buid, addr, 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);
> +    spapr_rtas_register(RTAS_IBM_RESET_PE_DMA_WINDOW,
> +                        "ibm,reset-pe-dma-window",
> +                        rtas_ibm_reset_pe_dma_window);
> +}
> +
> +type_init(spapr_rtas_ddw_init)
> diff --git a/trace-events b/trace-events
> index 04f5df2..9af53d9 100644
> --- a/trace-events
> +++ b/trace-events
> @@ -1285,6 +1285,10 @@ 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"
> +spapr_iommu_ddw_reset(uint64_t buid, uint32_t cfgaddr, long ret) 
> "buid=%"PRIx64" addr=%"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)"

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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