Re: [Qemu-devel] [PATCH 4/4] pc: add 'etc/pcimem64-minimum-address' fw_cfg interface to SeaBIOS

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Oct 16, 2013 at 02:19:13PM +0200, Igor Mammedov wrote:
> On Wed, 16 Oct 2013 12:29:48 +0300
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Wed, Oct 16, 2013 at 10:49:14AM +0200, Igor Mammedov wrote:
> > > 'etc/pcimem64-minimum-address' will allow QEMU to communicate to BIOS
> > > where PCI memory address space mapping starts in high memory.
> > > 
> > > Allowing BIOS start mapping 64-bit PCI BARs at address where QEMU
> > > placed this mapping vs. hardcoded value right after highmem RAM.
> > > 
> > > That will allow QEMU to reserve extra address space before
> > > 64-bit PCI hole for memory hotplug.
> > > 
> > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > > ---
> > >   * SeaBIOS patch: http://patchwork.ozlabs.org/patch/283623/
> > > 
> > > ---
> > >  hw/i386/pc.c         |    9 ++++++++-
> > >  hw/i386/pc_piix.c    |    2 +-
> > >  hw/pci-host/piix.c   |    5 +++--
> > >  hw/pci-host/q35.c    |    4 +++-
> > >  include/hw/i386/pc.h |    5 +++--
> > >  5 files changed, 18 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> > > index 7ecb028..ac99ae1 100644
> > > --- a/hw/i386/pc.c
> > > +++ b/hw/i386/pc.c
> > > @@ -1055,7 +1055,7 @@ PcGuestInfo *pc_guest_info_init(ram_addr_t below_4g_mem_size,
> > >  
> > >  /* setup pci memory regions mappings into system address space */
> > >  void pc_pci_as_mapping_init(Object *owner, MemoryRegion *system_memory,
> > > -                            MemoryRegion *pci_address_space,
> > > +                            MemoryRegion *pci_address_space, FWCfgState *fw_cfg,
> > >                              MemoryRegion *pci32_as, MemoryRegion *pci64_as,
> > >                              uint32_t pci32_as_start, uint32_t pci32_as_size,
> > >                              uint64_t pci64_as_start, uint64_t pci64_as_size)
> > > @@ -1083,6 +1083,13 @@ void pc_pci_as_mapping_init(Object *owner, MemoryRegion *system_memory,
> > >          memory_region_add_subregion(system_memory,
> > >                                      ROUND_UP(pci64_as_start, 0x1ULL << 30),
> > >                                      pci64_as);
> > > +        if (fw_cfg) {
> > > +            uint64_t *pcimem64_start = g_malloc(sizeof(*pcimem64_start));
> > > +
> > > +            *pcimem64_start = cpu_to_le64(pci64_as_start);
> > > +            fw_cfg_add_file(fw_cfg, "etc/pcimem64-minimum-address",
> > > +                            pcimem64_start, sizeof(*pcimem64_start));
> > > +        }
> > >      }
> > >  }
> > >  
> > > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> > > index 2fed5fd..966c48a 100644
> > > --- a/hw/i386/pc_piix.c
> > > +++ b/hw/i386/pc_piix.c
> > > @@ -148,7 +148,7 @@ static void pc_init1(QEMUMachineInitArgs *args,
> > >                                system_memory, system_io,
> > >                                below_4g_mem_size,
> > >                                above_4g_mem_size,
> > > -                              pci_memory, ram_memory);
> > > +                              pci_memory, ram_memory, fw_cfg);
> > >      } else {
> > >          pci_bus = NULL;
> > >          i440fx_state = NULL;
> > > diff --git a/hw/pci-host/piix.c b/hw/pci-host/piix.c
> > > index d422b25..9347099 100644
> > > --- a/hw/pci-host/piix.c
> > > +++ b/hw/pci-host/piix.c
> > > @@ -314,7 +314,8 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state,
> > >                      hwaddr below_4g_mem_size,
> > >                      ram_addr_t above_4g_mem_size,
> > >                      MemoryRegion *pci_address_space,
> > > -                    MemoryRegion *ram_memory)
> > > +                    MemoryRegion *ram_memory,
> > > +                    FWCfgState *fw_cfg)
> > >  {
> > >      DeviceState *dev;
> > >      PCIBus *b;
> > > @@ -353,7 +354,7 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state,
> > >      }
> > >  
> > >      pc_pci_as_mapping_init(OBJECT(d), f->system_memory,
> > > -                           f->pci_address_space,
> > > +                           f->pci_address_space, fw_cfg,
> > >                             &f->pci_hole, &f->pci_hole_64bit,
> > >                             below_4g_mem_size,
> > >                             0x100000000ULL - below_4g_mem_size,
> > > diff --git a/hw/pci-host/q35.c b/hw/pci-host/q35.c
> > > index cb8aea0..583585c 100644
> > > --- a/hw/pci-host/q35.c
> > > +++ b/hw/pci-host/q35.c
> > > @@ -30,6 +30,7 @@
> > >  #include "hw/hw.h"
> > >  #include "hw/pci-host/q35.h"
> > >  #include "qapi/visitor.h"
> > > +#include "hw/nvram/fw_cfg.h"
> > >  
> > >  /****************************************************************************
> > >   * Q35 host
> > > @@ -336,10 +337,11 @@ static int mch_init(PCIDevice *d)
> > >  {
> > >      int i;
> > >      MCHPCIState *mch = MCH_PCI_DEVICE(d);
> > > +    FWCfgState *fw_cfg = FW_CFG(object_resolve_path(FW_CFG_PATH, NULL));
> > 
> > Seems to duplicate code from fw_cfg_find().
> > Why not just use it?
> I've thought CAST(object_resolve_path()) is preferred method to do it,
> But I can surely use fw_cfg_find().

I've no idea what's preferable, but duplicating code generally
is considered a bad idea in C.

> > 
> > >  
> > >      /* setup pci memory regions */
> > >      pc_pci_as_mapping_init(OBJECT(mch), mch->system_memory,
> > > -                           mch->pci_address_space,
> > > +                           mch->pci_address_space, fw_cfg,
> > >                             &mch->pci_hole, &mch->pci_hole_64bit,
> > >                             mch->below_4g_mem_size,
> > >                             0x100000000ULL - mch->below_4g_mem_size,
> > 
> > Or call fw_cfg_find internally in pc_pci_as_mapping_init?
> I'll do it, thanks!
> 
> > 
> > > diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
> > > index ed86642..6d0d8c9 100644
> > > --- a/include/hw/i386/pc.h
> > > +++ b/include/hw/i386/pc.h
> > > @@ -110,7 +110,7 @@ PcGuestInfo *pc_guest_info_init(ram_addr_t below_4g_mem_size,
> > >  
> > >  
> > >  void pc_pci_as_mapping_init(Object *owner, MemoryRegion *system_memory,
> > > -                            MemoryRegion *pci_address_space,
> > > +                            MemoryRegion *pci_address_space, FWCfgState *fw_cfg,
> > >                              MemoryRegion *pci32_as, MemoryRegion *pci64_as,
> > >                              uint32_t pci32_as_start, uint32_t pci32_as_size,
> > >                              uint64_t pci64_as_start, uint64_t pci64_as_size);
> > > @@ -164,7 +164,8 @@ PCIBus *i440fx_init(PCII440FXState **pi440fx_state, int *piix_devfn,
> > >                      hwaddr below_4g_mem_size,
> > >                      ram_addr_t above_4g_mem_size,
> > >                      MemoryRegion *pci_memory,
> > > -                    MemoryRegion *ram_memory);
> > > +                    MemoryRegion *ram_memory,
> > > +                    FWCfgState *fw_cfg);
> > >  
> > >  /* piix4.c */
> > >  extern PCIDevice *piix4_dev;
> > > -- 
> > > 1.7.1