Re: [PATCH RFC] x86/hvm: unify HVM and PVH hypercall tables.

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, May 08, 2014 at 04:31:30PM +0100, Tim Deegan wrote:
> Stage one of many in merging PVH and HVM code in the hypervisor.
> 
> This exposes a few new hypercalls to HVM guests, all of which were
> already available to PVH ones:
> 
>  - XENMEM_memory_map / XENMEM_machine_memory_map / XENMEM_machphys_mapping:
>    These are basically harmless, if a bit useless to plain HVM.
> 
>  - VCPUOP_send_nmi / VCPUOP_initialise / VCPUOP[_is]_up / VCPUOP_down
>    This will eventually let HVM guests bring up APs the way PVH ones do.
>    For now, the VCPUOP_initialise paths are still gated on is_pvh.

I had a similar patch to enable this under HVM and found out that
if the guest issues VCPUOP_send_nmi we get in Linux:

[    3.611742] Corrupted low memory at c000fffc (fffc phys) = 00029b00
[    2.386785] Corrupted low memory at ffff88000000fff8 (fff8 phys) = 2990000000000

http://mid.gmane.org/20140422183443.GA6817@phenom.dumpdata.com


>  - VCPUOP_get_physid
>    Harmless.

The other VCPUOP_ ones are OK and you can stack an Reviewed-by-and-Tested-by:
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

on that.
> 
>  - __HYPERVISOR_platform_op (XSM_PRIV callers only).
> 
>  - __HYPERVISOR_mmuext_op.
>    The pagetable manipulation MMUEXT ops are already denied to
>    paging_mode_refcounts() domains; the baseptr ones are already
>    denied to paging_mode_translate() domains.
>    I have restricted MMUEXT[UN]MARK_SUPER to !paging_mode_refcounts()
>    domains as well, as I can see no need for them in PVH.
>    That leaves TLB and cache flush operations and MMUEXT_CLEAR_PAGE /
>    MMUEXT_COPY_PAGE, all of which are OK.
> 
>  - PHYSDEVOP_* (only for hardware control domains).
>    Also make ops that touch PV vcpu state (PHYSDEVOP_set_iopl and
>    PHYSDEVOP_set_iobitmap) gate on is_pv rather than !is_pvh.
> 
> PVH guests can also see a few hypercalls that they couldn't before,
> but which were already available to HVM guests:
> 
>  - __HYPERVISOR_set_timer_op
> 
>  - __HYPERVISOR_tmem_op
> 
> Signed-off-by: Tim Deegan <tim@xen.org>
> Cc: Keir Fraser <keir@xen.org>
> Cc: Jan Beulich <jbeulich@suse.com>
> Cc: Mukesh Rathor <mukesh.rathor@oracle.com>
> ---
>  xen/arch/x86/hvm/hvm.c          | 113 +++++++---------------------------------
>  xen/arch/x86/mm.c               |  12 +++++
>  xen/arch/x86/physdev.c          |   4 +-
>  xen/arch/x86/x86_64/compat/mm.c |   2 -
>  xen/include/asm-x86/hypercall.h |  10 ++++
>  5 files changed, 42 insertions(+), 99 deletions(-)
> 
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index da220bf..4274151 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -3433,16 +3433,13 @@ static long hvm_memory_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>  
>      switch ( cmd & MEMOP_CMD_MASK )
>      {
> -    case XENMEM_memory_map:
> -    case XENMEM_machine_memory_map:
> -    case XENMEM_machphys_mapping:
> -        return -ENOSYS;
>      case XENMEM_decrease_reservation:
>          rc = do_memory_op(cmd, arg);
>          current->domain->arch.hvm_domain.qemu_mapcache_invalidate = 1;
>          return rc;
> +    default:
> +        return do_memory_op(cmd, arg);
>      }
> -    return do_memory_op(cmd, arg);
>  }
>  
>  static long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
> @@ -3450,7 +3447,7 @@ static long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>      switch ( cmd )
>      {
>      default:
> -        if ( !is_pvh_vcpu(current) || !is_hardware_domain(current->domain) )
> +        if ( !is_hardware_domain(current->domain) )
>              return -ENOSYS;
>          /* fall through */
>      case PHYSDEVOP_map_pirq:
> @@ -3462,31 +3459,6 @@ static long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>      }
>  }
>  
> -static long hvm_vcpu_op(
> -    int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> -{
> -    long rc;
> -
> -    switch ( cmd )
> -    {
> -    case VCPUOP_register_runstate_memory_area:
> -    case VCPUOP_get_runstate_info:
> -    case VCPUOP_set_periodic_timer:
> -    case VCPUOP_stop_periodic_timer:
> -    case VCPUOP_set_singleshot_timer:
> -    case VCPUOP_stop_singleshot_timer:
> -    case VCPUOP_register_vcpu_info:
> -    case VCPUOP_register_vcpu_time_memory_area:
> -        rc = do_vcpu_op(cmd, vcpuid, arg);
> -        break;
> -    default:
> -        rc = -ENOSYS;
> -        break;
> -    }
> -
> -    return rc;
> -}
> -
>  typedef unsigned long hvm_hypercall_t(
>      unsigned long, unsigned long, unsigned long, unsigned long, unsigned long,
>      unsigned long);
> @@ -3509,41 +3481,13 @@ static long hvm_memory_op_compat32(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>  
>      switch ( cmd & MEMOP_CMD_MASK )
>      {
> -    case XENMEM_memory_map:
> -    case XENMEM_machine_memory_map:
> -    case XENMEM_machphys_mapping:
> -        return -ENOSYS;
>      case XENMEM_decrease_reservation:
>          rc = compat_memory_op(cmd, arg);
>          current->domain->arch.hvm_domain.qemu_mapcache_invalidate = 1;
>          return rc;
> -    }
> -    return compat_memory_op(cmd, arg);
> -}
> -
> -static long hvm_vcpu_op_compat32(
> -    int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> -{
> -    long rc;
> -
> -    switch ( cmd )
> -    {
> -    case VCPUOP_register_runstate_memory_area:
> -    case VCPUOP_get_runstate_info:
> -    case VCPUOP_set_periodic_timer:
> -    case VCPUOP_stop_periodic_timer:
> -    case VCPUOP_set_singleshot_timer:
> -    case VCPUOP_stop_singleshot_timer:
> -    case VCPUOP_register_vcpu_info:
> -    case VCPUOP_register_vcpu_time_memory_area:
> -        rc = compat_vcpu_op(cmd, vcpuid, arg);
> -        break;
>      default:
> -        rc = -ENOSYS;
> -        break;
> +        return compat_memory_op(cmd, arg);
>      }
> -
> -    return rc;
>  }
>  
>  static long hvm_physdev_op_compat32(
> @@ -3551,27 +3495,29 @@ static long hvm_physdev_op_compat32(
>  {
>      switch ( cmd )
>      {
> +    default:
> +        if ( !is_hardware_domain(current->domain) )
> +            return -ENOSYS;
> +        /* fall through */
>          case PHYSDEVOP_map_pirq:
>          case PHYSDEVOP_unmap_pirq:
>          case PHYSDEVOP_eoi:
>          case PHYSDEVOP_irq_status_query:
>          case PHYSDEVOP_get_free_pirq:
>              return compat_physdev_op(cmd, arg);
> -        break;
> -    default:
> -            return -ENOSYS;
> -        break;
>      }
>  }
>  
>  static hvm_hypercall_t *const hvm_hypercall64_table[NR_hypercalls] = {
>      [ __HYPERVISOR_memory_op ] = (hvm_hypercall_t *)hvm_memory_op,
>      [ __HYPERVISOR_grant_table_op ] = (hvm_hypercall_t *)hvm_grant_table_op,
> -    [ __HYPERVISOR_vcpu_op ] = (hvm_hypercall_t *)hvm_vcpu_op,
>      [ __HYPERVISOR_physdev_op ] = (hvm_hypercall_t *)hvm_physdev_op,
> +    HYPERCALL(platform_op),
>      HYPERCALL(xen_version),
>      HYPERCALL(console_io),
>      HYPERCALL(event_channel_op),
> +    HYPERCALL(vcpu_op),
> +    HYPERCALL(mmuext_op),
>      HYPERCALL(sched_op),
>      HYPERCALL(set_timer_op),
>      HYPERCALL(xsm_op),
> @@ -3587,11 +3533,13 @@ static hvm_hypercall_t *const hvm_hypercall64_table[NR_hypercalls] = {
>  static hvm_hypercall_t *const hvm_hypercall32_table[NR_hypercalls] = {
>      [ __HYPERVISOR_memory_op ] = (hvm_hypercall_t *)hvm_memory_op_compat32,
>      [ __HYPERVISOR_grant_table_op ] = (hvm_hypercall_t *)hvm_grant_table_op_compat32,
> -    [ __HYPERVISOR_vcpu_op ] = (hvm_hypercall_t *)hvm_vcpu_op_compat32,
>      [ __HYPERVISOR_physdev_op ] = (hvm_hypercall_t *)hvm_physdev_op_compat32,
> +    HYPERCALL(platform_op),
>      COMPAT_CALL(xen_version),
>      HYPERCALL(console_io),
>      HYPERCALL(event_channel_op),
> +    COMPAT_CALL(vcpu_op),
> +    COMPAT_CALL(mmuext_op),
>      COMPAT_CALL(sched_op),
>      COMPAT_CALL(set_timer_op),
>      HYPERCALL(xsm_op),
> @@ -3601,24 +3549,6 @@ static hvm_hypercall_t *const hvm_hypercall32_table[NR_hypercalls] = {
>      HYPERCALL(tmem_op)
>  };
>  
> -/* PVH 32bitfixme. */
> -static hvm_hypercall_t *const pvh_hypercall64_table[NR_hypercalls] = {
> -    HYPERCALL(platform_op),
> -    HYPERCALL(memory_op),
> -    HYPERCALL(xen_version),
> -    HYPERCALL(console_io),
> -    [ __HYPERVISOR_grant_table_op ]  = (hvm_hypercall_t *)hvm_grant_table_op,
> -    HYPERCALL(vcpu_op),
> -    HYPERCALL(mmuext_op),
> -    HYPERCALL(xsm_op),
> -    HYPERCALL(sched_op),
> -    HYPERCALL(event_channel_op),
> -    [ __HYPERVISOR_physdev_op ]      = (hvm_hypercall_t *)hvm_physdev_op,
> -    HYPERCALL(hvm_op),
> -    HYPERCALL(sysctl),
> -    HYPERCALL(domctl)
> -};
> -
>  int hvm_do_hypercall(struct cpu_user_regs *regs)
>  {
>      struct vcpu *curr = current;
> @@ -3645,9 +3575,7 @@ int hvm_do_hypercall(struct cpu_user_regs *regs)
>      if ( (eax & 0x80000000) && is_viridian_domain(curr->domain) )
>          return viridian_hypercall(regs);
>  
> -    if ( (eax >= NR_hypercalls) ||
> -         (is_pvh_vcpu(curr) ? !pvh_hypercall64_table[eax]
> -                            : !hvm_hypercall32_table[eax]) )
> +    if ( (eax >= NR_hypercalls) || !hvm_hypercall32_table[eax] )
>      {
>          regs->eax = -ENOSYS;
>          return HVM_HCALL_completed;
> @@ -3662,14 +3590,9 @@ int hvm_do_hypercall(struct cpu_user_regs *regs)
>                      regs->r10, regs->r8, regs->r9);
>  
>          curr->arch.hvm_vcpu.hcall_64bit = 1;
> -        if ( is_pvh_vcpu(curr) )
> -            regs->rax = pvh_hypercall64_table[eax](regs->rdi, regs->rsi,
> -                                                   regs->rdx, regs->r10,
> -                                                   regs->r8, regs->r9);
> -        else
> -            regs->rax = hvm_hypercall64_table[eax](regs->rdi, regs->rsi,
> -                                                   regs->rdx, regs->r10,
> -                                                   regs->r8, regs->r9);
> +        regs->rax = hvm_hypercall64_table[eax](regs->rdi, regs->rsi,
> +                                               regs->rdx, regs->r10,
> +                                               regs->r8, regs->r9);
>          curr->arch.hvm_vcpu.hcall_64bit = 0;
>      }
>      else
> diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
> index 1a8a5e0..3d5c3c8 100644
> --- a/xen/arch/x86/mm.c
> +++ b/xen/arch/x86/mm.c
> @@ -3310,6 +3310,12 @@ long do_mmuext_op(
>              unsigned long mfn;
>              struct spage_info *spage;
>  
> +            if ( paging_mode_refcounts(pg_owner) )
> +            {
> +                okay = 0;
> +                break;
> +            }
> +
>              mfn = op.arg1.mfn;
>              if ( mfn & (L1_PAGETABLE_ENTRIES-1) )
>              {
> @@ -3336,6 +3342,12 @@ long do_mmuext_op(
>              unsigned long mfn;
>              struct spage_info *spage;
>  
> +            if ( paging_mode_refcounts(pg_owner) )
> +            {
> +                okay = 0;
> +                break;
> +            }
> +
>              mfn = op.arg1.mfn;
>              if ( mfn & (L1_PAGETABLE_ENTRIES-1) )
>              {
> diff --git a/xen/arch/x86/physdev.c b/xen/arch/x86/physdev.c
> index f178315..a2d2b96 100644
> --- a/xen/arch/x86/physdev.c
> +++ b/xen/arch/x86/physdev.c
> @@ -520,7 +520,7 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>          struct physdev_set_iopl set_iopl;
>  
>          ret = -ENOSYS;
> -        if ( is_pvh_vcpu(current) )
> +        if ( !is_pv_vcpu(current) )
>              break;
>  
>          ret = -EFAULT;
> @@ -538,7 +538,7 @@ ret_t do_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>          struct physdev_set_iobitmap set_iobitmap;
>  
>          ret = -ENOSYS;
> -        if ( is_pvh_vcpu(current) )
> +        if ( !is_pv_vcpu(current) )
>              break;
>  
>          ret = -EFAULT;
> diff --git a/xen/arch/x86/x86_64/compat/mm.c b/xen/arch/x86/x86_64/compat/mm.c
> index 69c6195..3fa90aa 100644
> --- a/xen/arch/x86/x86_64/compat/mm.c
> +++ b/xen/arch/x86/x86_64/compat/mm.c
> @@ -236,8 +236,6 @@ int compat_update_va_mapping_otherdomain(unsigned long va, u32 lo, u32 hi,
>      return do_update_va_mapping_otherdomain(va, lo | ((u64)hi << 32), flags, domid);
>  }
>  
> -DEFINE_XEN_GUEST_HANDLE(mmuext_op_compat_t);
> -
>  int compat_mmuext_op(XEN_GUEST_HANDLE_PARAM(mmuext_op_compat_t) cmp_uops,
>                       unsigned int count,
>                       XEN_GUEST_HANDLE_PARAM(uint) pdone,
> diff --git a/xen/include/asm-x86/hypercall.h b/xen/include/asm-x86/hypercall.h
> index afa8ba9..cee8817 100644
> --- a/xen/include/asm-x86/hypercall.h
> +++ b/xen/include/asm-x86/hypercall.h
> @@ -8,6 +8,7 @@
>  #include <public/physdev.h>
>  #include <public/arch-x86/xen-mca.h> /* for do_mca */
>  #include <xen/types.h>
> +#include <compat/memory.h>
>  
>  /*
>   * Both do_mmuext_op() and do_mmu_update():
> @@ -110,4 +111,13 @@ extern int
>  arch_compat_vcpu_op(
>      int cmd, struct vcpu *v, XEN_GUEST_HANDLE_PARAM(void) arg);
>  
> +DEFINE_XEN_GUEST_HANDLE(mmuext_op_compat_t);
> +
> +extern int
> +compat_mmuext_op(
> +    XEN_GUEST_HANDLE_PARAM(mmuext_op_compat_t) cmp_uops,
> +    unsigned int count,
> +    XEN_GUEST_HANDLE_PARAM(uint) pdone,
> +    unsigned int foreigndom);
> +
>  #endif /* __ASM_X86_HYPERCALL_H__ */
> -- 
> 1.8.5.2
> 
> 
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