Re: [Xen-devel] [PATCH v4 04/24] arm/acpi: Estimate memory required for acpi/efi tables

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 1 Mar 2016, Shannon Zhao wrote:
> On 2016/2/29 20:13, Stefano Stabellini wrote:
> > On Sun, 28 Feb 2016, Shannon Zhao wrote:
> >> > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> >> > 
> >> > Estimate the memory required for loading acpi/efi tables in Dom0. Make
> >> > the length of each table aligned with 64bit. Alloc the pages to store
> >> > the new created EFI and ACPI tables and free these pages when
> >> > destroying domain.
> >> > 
> >> > Cc: Jan Beulich <jbeulich@xxxxxxxx>
> >> > Signed-off-by: Parth Dixit <parth.dixit@xxxxxxxxxx>
> >> > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> >> > ---
> >> > v4: make the length of each table aligned with 64bit
> >> > ---
> >> >  xen/arch/arm/domain.c       |  4 +++
> >> >  xen/arch/arm/domain_build.c | 81 
> >> > ++++++++++++++++++++++++++++++++++++++++++++-
> >> >  xen/common/efi/boot.c       | 20 +++++++++++
> >> >  xen/include/asm-arm/setup.h |  2 ++
> >> >  4 files changed, 106 insertions(+), 1 deletion(-)
> >> > 
> >> > diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> >> > index 3d274ae..1365b4a 100644
> >> > --- a/xen/arch/arm/domain.c
> >> > +++ b/xen/arch/arm/domain.c
> >> > @@ -640,6 +640,10 @@ void arch_domain_destroy(struct domain *d)
> >> >      domain_vgic_free(d);
> >> >      domain_vuart_free(d);
> >> >      free_xenheap_page(d->shared_info);
> >> > +#ifdef CONFIG_ACPI
> >> > +    free_xenheap_pages(d->arch.efi_acpi_table,
> >> > +                       get_order_from_bytes(d->arch.efi_acpi_len));
> >> > +#endif
> >> >  }
> >> >  
> >> >  void arch_domain_shutdown(struct domain *d)
> >> > diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> >> > index 83676e4..b10a69d 100644
> >> > --- a/xen/arch/arm/domain_build.c
> >> > +++ b/xen/arch/arm/domain_build.c
> >> > @@ -12,6 +12,8 @@
> >> >  #include <xen/libfdt/libfdt.h>
> >> >  #include <xen/guest_access.h>
> >> >  #include <xen/iocap.h>
> >> > +#include <xen/acpi.h>
> >> > +#include <acpi/actables.h>
> >> >  #include <asm/device.h>
> >> >  #include <asm/setup.h>
> >> >  #include <asm/platform.h>
> >> > @@ -1354,6 +1356,79 @@ static int prepare_dtb(struct domain *d, struct 
> >> > kernel_info *kinfo)
> >> >      return -EINVAL;
> >> >  }
> >> >  
> >> > +#ifdef CONFIG_ACPI
> >> > +static int estimate_acpi_efi_size(struct domain *d, struct kernel_info 
> >> > *kinfo)
> >> > +{
> >> > +    u64 efi_size, acpi_size = 0, addr;
> >> > +    u32 madt_size;
> >> > +    struct acpi_table_rsdp *rsdp_tbl;
> >> > +    struct acpi_table_header *table = NULL;
> >> > +
> >> > +    efi_size = estimate_efi_size(kinfo->mem.nr_banks);
> >> > +
> >> > +    acpi_size += ROUNDUP(sizeof(struct acpi_table_fadt), 8);
> >> > +    acpi_size += ROUNDUP(sizeof(struct acpi_table_stao), 8);
> >> > +
> >> > +    madt_size = sizeof(struct acpi_table_madt)
> >> > +                + sizeof(struct acpi_madt_generic_interrupt) * 
> >> > d->max_vcpus
> >> > +                + sizeof(struct acpi_madt_generic_distributor);
> >> > +    if ( d->arch.vgic.version == GIC_V3 )
> >> > +        madt_size += sizeof(struct acpi_madt_generic_redistributor)
> >> > +                     * d->arch.vgic.nr_regions;
> >> > +    acpi_size += ROUNDUP(madt_size, 8);
> >> > +
> >> > +    addr = acpi_os_get_root_pointer();
> >> > +    if ( !addr )
> >> > +    {
> >> > +        printk("Unable to get acpi root pointer\n");
> >> > +        return -EINVAL;
> >> > +    }
> >> > +    rsdp_tbl = acpi_os_map_memory(addr, sizeof(struct acpi_table_rsdp));
> >> > +    table = acpi_os_map_memory(rsdp_tbl->xsdt_physical_address,
> >> > +                               sizeof(struct acpi_table_header));
> >> > +    /* Add place for STAO table in XSDT table */
> >> > +    acpi_size += ROUNDUP(table->length + sizeof(u64), 8);
> >> > +    acpi_os_unmap_memory(table, sizeof(struct acpi_table_header));
> >> > +    acpi_os_unmap_memory(rsdp_tbl, sizeof(struct acpi_table_rsdp));
> >> > +
> >> > +    acpi_size += ROUNDUP(sizeof(struct acpi_table_rsdp), 8);
> >> > +    d->arch.efi_acpi_len = ROUNDUP(efi_size, 8) + ROUNDUP(acpi_size, 8);
> >> > +
> >> > +    return 0;
> >> > +}
> >> > +
> >> > +static int prepare_acpi(struct domain *d, struct kernel_info *kinfo)
> >> > +{
> >> > +    int rc = 0;
> >> > +    int order;
> >> > +
> >> > +    rc = estimate_acpi_efi_size(d, kinfo);
> >> > +    if ( rc != 0 )
> >> > +        return rc;
> >> > +
> >> > +    order = get_order_from_bytes(d->arch.efi_acpi_len);
> >> > +    d->arch.efi_acpi_table = alloc_xenheap_pages(order, 0);
> >> > +    if ( d->arch.efi_acpi_table == NULL )
> >> > +    {
> >> > +        printk("unable to allocate memory!\n");
> >> > +        return -ENOMEM;
> >> > +    }
> >> > +    memset(d->arch.efi_acpi_table, 0, d->arch.efi_acpi_len);
> >> > +
> >> > +    /* For ACPI, Dom0 doesn't use kinfo->gnttab_start to get the grant 
> >> > table
> >> > +     * region. So we use it as the ACPI table mapped address. */
> >> > +    d->arch.efi_acpi_gpa = kinfo->gnttab_start;
> >> > +
> >> > +    return 0;
> >> > +}
> >> > +#else
> >> > +static int prepare_acpi(struct domain *d, struct kernel_info *kinfo)
> >> > +{
> >> > +    /* Only booting with ACPI will hit here */
> >> > +    BUG_ON(1);
> >> > +    return -EINVAL;
> >> > +}
> >> > +#endif
> >> >  static void dtb_load(struct kernel_info *kinfo)
> >> >  {
> >> >      void * __user dtb_virt = (void * 
> >> > __user)(register_t)kinfo->dtb_paddr;
> >> > @@ -1540,7 +1615,11 @@ int construct_dom0(struct domain *d)
> >> >      allocate_memory(d, &kinfo);
> >> >      find_gnttab_region(d, &kinfo);
> >> >  
> >> > -    rc = prepare_dtb(d, &kinfo);
> >> > +    if ( acpi_disabled )
> >> > +        rc = prepare_dtb(d, &kinfo);
> >> > +    else
> >> > +        rc = prepare_acpi(d, &kinfo);
> >> > +
> >> >      if ( rc < 0 )
> >> >          return rc;
> >> >  
> >> > diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
> >> > index 53c7452..535c685 100644
> >> > --- a/xen/common/efi/boot.c
> >> > +++ b/xen/common/efi/boot.c
> >> > @@ -13,6 +13,7 @@
> >> >  #include <xen/multiboot.h>
> >> >  #include <xen/pci_regs.h>
> >> >  #include <xen/pfn.h>
> >> > +#include <asm/acpi.h>
> >> >  #if EFI_PAGE_SIZE != PAGE_SIZE
> >> >  # error Cannot use xen/pfn.h here!
> >> >  #endif
> >> > @@ -1171,6 +1172,25 @@ efi_start(EFI_HANDLE ImageHandle, 
> >> > EFI_SYSTEM_TABLE *SystemTable)
> >> >      for( ; ; ); /* not reached */
> >> >  }
> >> >  
> >> > +#if defined (CONFIG_ACPI) && defined (CONFIG_ARM)
> >> > +/* Constant to indicate "Xen" in unicode u16 format */
> >> > +static const u16 XEN_EFI_FW_VENDOR[] ={0x0058,0x0065,0x006E,0x0000};
> >> > +
> >> > +int __init estimate_efi_size(int mem_nr_banks)
> >> > +{
> >> > +    int size = 0;
> >> > +    int est_size = sizeof(EFI_SYSTEM_TABLE);
> >> > +    int ect_size = sizeof(EFI_CONFIGURATION_TABLE);
> >> > +    int emd_size = sizeof(EFI_MEMORY_DESCRIPTOR);
> >> > +    int fw_vendor_size = sizeof(XEN_EFI_FW_VENDOR);
> >> > +
> >> > +    size += ROUNDUP((est_size + ect_size + fw_vendor_size), 8);
> >> > +    size += ROUNDUP(emd_size * (mem_nr_banks + acpi_mem.nr_banks + 1), 
> >> > 8);
> >> > +
> >> > +    return size;
> >> > +}
> >> > +#endif
> > Given that EFI and ACPI are separate things, I don't think we should
> > ifdef CONFIG_ACPI this function. estimate_efi_size should work even if
> > no ACPI tables are present, right?
> > 
> Yes, while we could check acpi_disabled to know whether Xen boots with
> ACPI, is there any way to check if Xen boots with UEFI(especially UEFI +
> DT)?

There is an efi_enabled variable, but that is 0 on ARM because runtime
services are not implemented yet. But it is OK to assume that on ARM if
ACPI is enabled, efi is also enabled.

That said, these are runtime checks, while the problem with the code in
this patch is a compile-time #ifdef.

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