diff mbox

[Xen-devel,VMID,2/2,v3] xen/arm: Add support for 16 bit VMIDs

Message ID 1481527598-15423-2-git-send-email-bhupinder.thakur@linaro.org
State Superseded
Headers show

Commit Message

Bhupinder Thakur Dec. 12, 2016, 7:26 a.m. UTC 
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@linaro.org>
---
 xen/arch/arm/p2m.c              | 56 ++++++++++++++++++++++++++++++++++-------
 xen/include/asm-arm/p2m.h       |  2 +-
 xen/include/asm-arm/processor.h | 18 ++++++++++++-
 3 files changed, 65 insertions(+), 11 deletions(-)

Comments

Julien Grall Dec. 13, 2016, 2:13 p.m. UTC | #1 
Hi Bhupinder,

On 12/12/16 07:26, Bhupinder Thakur wrote:

[...]

> -void p2m_vmid_allocator_init(void)
> +int p2m_vmid_allocator_init(void)
>  {
> -    set_bit(INVALID_VMID, vmid_mask);
> +    int ret = 0;
> +
> +    /*
> +     * allocate space for vmid_mask based on MAX_VMID
> +     */
> +    vmid_mask = xzalloc_array(unsigned long, BITS_TO_LONGS(MAX_VMID));

I would directly handle the panic within this function rather than 
return an error. I.e

if ( !vmid_mask )
   panic(....);

This would simplify the logic a bit.

> +
> +    if ( vmid_mask )
> +        set_bit(INVALID_VMID, vmid_mask);
> +    else
> +        ret = -1;
> +
> +    return ret;
>  }
>
>  static int p2m_alloc_vmid(struct domain *d)
> @@ -1632,20 +1653,36 @@ void __init setup_virt_paging(void)
>
>      unsigned int cpu;
>      unsigned int pa_range = 0x10; /* Larger than any possible value */
> +    unsigned int vmid_8_bit_flag = 0;

Please use bool:

bool vmid_8_bit_flag = false;

I would also drop _flag as it is not necessary.

>
>      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 suppot 16 bit VMIDs */
> +        if ( info->mm64.vmid_bits != MM64_VMID_16_BITS_SUPPORT )
> +            vmid_8_bit_flag = 1;

s/1/true/

The rest of the patch looks good to me.

Cheers,
Bhupinder Thakur Dec. 15, 2016, 6:04 a.m. UTC | #2 
Hi Julien,


On 13 December 2016 at 19:43, Julien Grall <julien.grall@arm.com> wrote:
> Hi Bhupinder,
>
> On 12/12/16 07:26, Bhupinder Thakur wrote:
>
> [...]
>
>> -void p2m_vmid_allocator_init(void)
>> +int p2m_vmid_allocator_init(void)
>>  {
>> -    set_bit(INVALID_VMID, vmid_mask);
>> +    int ret = 0;
>> +
>> +    /*
>> +     * allocate space for vmid_mask based on MAX_VMID
>> +     */
>> +    vmid_mask = xzalloc_array(unsigned long, BITS_TO_LONGS(MAX_VMID));
>
>
> I would directly handle the panic within this function rather than return an
> error. I.e
>
> if ( !vmid_mask )
>   panic(....);
>
> This would simplify the logic a bit.
>
ok. I will modify the code accordingly.


>>  static int p2m_alloc_vmid(struct domain *d)
>> @@ -1632,20 +1653,36 @@ void __init setup_virt_paging(void)
>>
>>      unsigned int cpu;
>>      unsigned int pa_range = 0x10; /* Larger than any possible value */
>> +    unsigned int vmid_8_bit_flag = 0;
>
>
> Please use bool:
>
> bool vmid_8_bit_flag = false;
>
> I would also drop _flag as it is not necessary.
ok. I will modify the code accordingly.

>
>>
>>      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 suppot 16 bit VMIDs */
>> +        if ( info->mm64.vmid_bits != MM64_VMID_16_BITS_SUPPORT )
>> +            vmid_8_bit_flag = 1;
>
>
> s/1/true/
>
ok

> The rest of the patch looks good to me.
>
> Cheers,
>
> --
> Julien Grall
diff mbox

Patch

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index d155c1d..0c98616 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 +15,23 @@ 
 #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;
+#define MAX_VMID       max_vmid
 #else
 /* First level P2M is alway 2 consecutive pages */
 #define P2M_ROOT_LEVEL 1
 #define P2M_ROOT_ORDER    1
+#define MAX_VMID        MAX_VMID_8_BIT
 #endif
 
 #define P2M_ROOT_PAGES    (1<<P2M_ROOT_ORDER)
@@ -1219,7 +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
@@ -1230,20 +1239,32 @@  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 supports 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;
 
-void p2m_vmid_allocator_init(void)
+int p2m_vmid_allocator_init(void)
 {
-    set_bit(INVALID_VMID, vmid_mask);
+    int ret = 0;
+
+    /*
+     * allocate space for vmid_mask based on MAX_VMID
+     */
+    vmid_mask = xzalloc_array(unsigned long, BITS_TO_LONGS(MAX_VMID));
+
+    if ( vmid_mask )
+        set_bit(INVALID_VMID, vmid_mask);
+    else
+        ret = -1;
+
+    return ret;
 }
 
 static int p2m_alloc_vmid(struct domain *d)
@@ -1632,20 +1653,36 @@  void __init setup_virt_paging(void)
 
     unsigned int cpu;
     unsigned int pa_range = 0x10; /* Larger than any possible value */
+    unsigned int vmid_8_bit_flag = 0;
 
     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 suppot 16 bit VMIDs */
+        if ( info->mm64.vmid_bits != MM64_VMID_16_BITS_SUPPORT )
+            vmid_8_bit_flag = 1;
     }
 
+    /* 
+     * if the flag is not set then it means all CPUs support 16-bit
+     * VMIDs.
+     */
+    if ( !vmid_8_bit_flag )
+        max_vmid = MAX_VMID_16_BIT;
+
     /* pa_range is 4 bits, but the defined encodings are only 3 bits */
     if ( pa_range&0x8 || !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);
 
@@ -1660,7 +1697,8 @@  void __init setup_virt_paging(void)
     printk("P2M: %d levels with order-%d root, VTCR 0x%lx\n",
            4 - P2M_ROOT_LEVEL, P2M_ROOT_ORDER, val);
 
-    p2m_vmid_allocator_init();
+    if ( p2m_vmid_allocator_init() != 0 )
+        panic("Could not allocate VMID bitmap space");
 
     /* It is not allowed to concatenate a level zero root */
     BUG_ON( P2M_ROOT_LEVEL == 0 && P2M_ROOT_ORDER > 0 );
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 15bf890..48ce59b 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 {