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Re: [Xen-devel] [XEN VMID PATCH v5 2/2] xen/arm: Add support for 16 bit VMIDs



Hi Julien,

I did not send the 1st patch in the series as there is no change in
the first patch since the last one I sent. I understood from your last
mail that I need not send the patch again if there is no change.

Should I send it again after updating the version as 5? Should I add
the reviewed-by tag in the first patch in the series?

Regards,
Bhupinder

On 15 December 2016 at 22:32, Julien Grall <julien.grall@xxxxxxx> wrote:
> Hi,
>
> The patch indicates "2/2" but I can't find the first patch. Is it a mistake?
>
> Cheers,
>
>
> On 15/12/2016 16:55, Bhupinder Thakur wrote:
>>
>> VMID space is increased to 16-bits from 8-bits in ARMv8 8.1 revision.
>> This allows more than 256 VMs to be supported by Xen.
>>
>> This change adds support for 16-bit VMIDs in Xen based on whether the
>> architecture supports it.
>>
>> Signed-off-by: Bhupinder Thakur <bhupinder.thakur@xxxxxxxxxx>
>> ---
>>  xen/arch/arm/p2m.c              | 52
>> ++++++++++++++++++++++++++++++++++-------
>>  xen/include/asm-arm/p2m.h       |  2 +-
>>  xen/include/asm-arm/processor.h | 18 +++++++++++++-
>>  3 files changed, 62 insertions(+), 10 deletions(-)
>>
>> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
>> index 6930f8c..61b9e49 100644
>> --- a/xen/arch/arm/p2m.c
>> +++ b/xen/arch/arm/p2m.c
>> @@ -7,6 +7,7 @@
>>  #include <xen/vm_event.h>
>>  #include <xen/monitor.h>
>>  #include <xen/iocap.h>
>> +#include <xen/xmalloc.h>
>>  #include <public/vm_event.h>
>>  #include <asm/flushtlb.h>
>>  #include <asm/gic.h>
>> @@ -14,15 +15,25 @@
>>  #include <asm/hardirq.h>
>>  #include <asm/page.h>
>>
>> +#define MAX_VMID_8_BIT  (1UL << 8)
>> +#define MAX_VMID_16_BIT (1UL << 16)
>> +
>> +#define INVALID_VMID 0 /* VMID 0 is reserved */
>> +
>>  #ifdef CONFIG_ARM_64
>>  static unsigned int __read_mostly p2m_root_order;
>>  static unsigned int __read_mostly p2m_root_level;
>>  #define P2M_ROOT_ORDER    p2m_root_order
>>  #define P2M_ROOT_LEVEL p2m_root_level
>> +static unsigned int __read_mostly max_vmid = MAX_VMID_8_BIT;
>> +/* VMID is by default 8 bit width on AArch64 */
>> +#define MAX_VMID       max_vmid
>>  #else
>>  /* First level P2M is alway 2 consecutive pages */
>>  #define P2M_ROOT_LEVEL 1
>>  #define P2M_ROOT_ORDER    1
>> +/* VMID is always 8 bit width on AArch32 */
>> +#define MAX_VMID        MAX_VMID_8_BIT
>>  #endif
>>
>>  #define P2M_ROOT_PAGES    (1<<P2M_ROOT_ORDER)
>> @@ -1217,7 +1228,7 @@ static int p2m_alloc_table(struct domain *d)
>>
>>      p2m->root = page;
>>
>> -    p2m->vttbr = page_to_maddr(p2m->root) | ((uint64_t)p2m->vmid & 0xff)
>> << 48;
>> +    p2m->vttbr = page_to_maddr(p2m->root) | ((uint64_t)p2m->vmid << 48);
>>
>>      /*
>>       * Make sure that all TLBs corresponding to the new VMID are flushed
>> @@ -1228,19 +1239,27 @@ static int p2m_alloc_table(struct domain *d)
>>      return 0;
>>  }
>>
>> -#define MAX_VMID 256
>> -#define INVALID_VMID 0 /* VMID 0 is reserved */
>>
>>  static spinlock_t vmid_alloc_lock = SPIN_LOCK_UNLOCKED;
>>
>>  /*
>> - * VTTBR_EL2 VMID field is 8 bits. Using a bitmap here limits us to
>> - * 256 concurrent domains.
>> + * VTTBR_EL2 VMID field is 8 or 16 bits. AArch64 may support 16-bit VMID.
>> + * Using a bitmap here limits us to 256 or 65536 (for AArch64) concurrent
>> + * domains. The bitmap space will be allocated dynamically based on
>> + * whether 8 or 16 bit VMIDs are supported.
>>   */
>> -static DECLARE_BITMAP(vmid_mask, MAX_VMID);
>> +static unsigned long *vmid_mask;
>>
>>  static void p2m_vmid_allocator_init(void)
>>  {
>> +    /*
>> +     * allocate space for vmid_mask based on MAX_VMID
>> +     */
>> +    vmid_mask = xzalloc_array(unsigned long, BITS_TO_LONGS(MAX_VMID));
>> +
>> +    if ( !vmid_mask )
>> +        panic("Could not allocate VMID bitmap space");
>> +
>>      set_bit(INVALID_VMID, vmid_mask);
>>  }
>>
>> @@ -1630,20 +1649,36 @@ void __init setup_virt_paging(void)
>>
>>      unsigned int cpu;
>>      unsigned int pa_range = 0x10; /* Larger than any possible value */
>> +    bool vmid_8_bit = false;
>>
>>      for_each_online_cpu ( cpu )
>>      {
>>          const struct cpuinfo_arm *info = &cpu_data[cpu];
>>          if ( info->mm64.pa_range < pa_range )
>>              pa_range = info->mm64.pa_range;
>> +
>> +        /* Set a flag if the current cpu does not support 16 bit VMIDs.
>> */
>> +        if ( info->mm64.vmid_bits != MM64_VMID_16_BITS_SUPPORT )
>> +            vmid_8_bit = true;
>>      }
>>
>> +    /*
>> +     * If the flag is not set then it means all CPUs support 16-bit
>> +     * VMIDs.
>> +     */
>> +    if ( !vmid_8_bit )
>> +        max_vmid = MAX_VMID_16_BIT;
>> +
>>      /* pa_range is 4 bits, but the defined encodings are only 3 bits */
>>      if ( pa_range >= ARRAY_SIZE(pa_range_info) ||
>> !pa_range_info[pa_range].pabits )
>>          panic("Unknown encoding of ID_AA64MMFR0_EL1.PARange %x\n",
>> pa_range);
>>
>>      val |= VTCR_PS(pa_range);
>>      val |= VTCR_TG0_4K;
>> +
>> +    /* Set the VS bit only if 16 bit VMID is supported. */
>> +    if ( MAX_VMID == MAX_VMID_16_BIT )
>> +        val |= VTCR_VS;
>>      val |= VTCR_SL0(pa_range_info[pa_range].sl0);
>>      val |= VTCR_T0SZ(pa_range_info[pa_range].t0sz);
>>
>> @@ -1651,9 +1686,10 @@ void __init setup_virt_paging(void)
>>      p2m_root_level = 2 - pa_range_info[pa_range].sl0;
>>      p2m_ipa_bits = 64 - pa_range_info[pa_range].t0sz;
>>
>> -    printk("P2M: %d-bit IPA with %d-bit PA\n",
>> +    printk("P2M: %d-bit IPA with %d-bit PA and %d-bit VMID\n",
>>             p2m_ipa_bits,
>> -           pa_range_info[pa_range].pabits);
>> +           pa_range_info[pa_range].pabits,
>> +           ( MAX_VMID == MAX_VMID_16_BIT )?16:8);
>>  #endif
>>      printk("P2M: %d levels with order-%d root, VTCR 0x%lx\n",
>>             4 - P2M_ROOT_LEVEL, P2M_ROOT_ORDER, val);
>> diff --git a/xen/include/asm-arm/p2m.h b/xen/include/asm-arm/p2m.h
>> index 0987be2..9de55fc 100644
>> --- a/xen/include/asm-arm/p2m.h
>> +++ b/xen/include/asm-arm/p2m.h
>> @@ -30,7 +30,7 @@ struct p2m_domain {
>>      struct page_info *root;
>>
>>      /* Current VMID in use */
>> -    uint8_t vmid;
>> +    uint16_t vmid;
>>
>>      /* Current Translation Table Base Register for the p2m */
>>      uint64_t vttbr;
>> diff --git a/xen/include/asm-arm/processor.h
>> b/xen/include/asm-arm/processor.h
>> index 4163884..afc0e9a 100644
>> --- a/xen/include/asm-arm/processor.h
>> +++ b/xen/include/asm-arm/processor.h
>> @@ -215,6 +215,8 @@
>>
>>  #define VTCR_PS(x)      ((x)<<16)
>>
>> +#define VTCR_VS            (_AC(0x1,UL)<<19)
>> +
>>  #endif
>>
>>  #define VTCR_RES1       (_AC(1,UL)<<31)
>> @@ -269,6 +271,11 @@
>>  /* FSR long format */
>>  #define FSRL_STATUS_DEBUG       (_AC(0x22,UL)<<0)
>>
>> +#ifdef CONFIG_ARM_64
>> +#define MM64_VMID_8_BITS_SUPPORT    0x0
>> +#define MM64_VMID_16_BITS_SUPPORT   0x2
>> +#endif
>> +
>>  #ifndef __ASSEMBLY__
>>
>>  struct cpuinfo_arm {
>> @@ -337,7 +344,16 @@ struct cpuinfo_arm {
>>              unsigned long tgranule_64K:4;
>>              unsigned long tgranule_4K:4;
>>              unsigned long __res0:32;
>> -       };
>> +
>> +            unsigned long hafdbs:4;
>> +            unsigned long vmid_bits:4;
>> +            unsigned long vh:4;
>> +            unsigned long hpds:4;
>> +            unsigned long lo:4;
>> +            unsigned long pan:4;
>> +            unsigned long __res1:8;
>> +            unsigned long __res2:32;
>> +        };
>>      } mm64;
>>
>>      struct {
>>
>
> --
> Julien Grall

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