xen/x86: remove XENFEAT_hvm_pirqs for PVHv2 guests

PVHv2 guests, unlike HVM guests, won't have the option to route interrupts
from physical or emulated devices over event channels using PIRQs. This
applies to both DomU and Dom0 PVHv2 guests.

Introduce a new XEN_X86_EMU_USE_PIRQ to notify Xen whether a HVM guest can
route physical interrupts (even from emulated devices) over event channels,
and is thus allowed to use some of the PHYSDEV ops.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
---
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
---
Changes since v6:
 - Rebase on top of the HVM hypercall changes (and drop Andrew's RB).

Changes since v5:
 - Introduce a has_pirq macro to match other XEN_X86_EMU_ options, and simplify
   some of the code.

Changes since v3:
 - Update docs.

Changes since v2:
 - Change local variable name to currd instead of d.
 - Use currd where it makes sense.

diff --git a/docs/misc/hvmlite.markdown b/docs/misc/hvmlite.markdown
index 898b8ee8021e6e8b107b1d9b133d84162d1d4699..b2557f7b098e0493decde21e636953b6ba8a379c 100644 (file)
--- a/docs/misc/hvmlite.markdown
+++ b/docs/misc/hvmlite.markdown
@@ -75,3 +75,23 @@ info structure that's passed at boot time (field rsdp_paddr).
 
 Description of paravirtualized devices will come from XenStore, just as it's
 done for HVM guests.
+
+## Interrupts ##
+
+### Interrupts from physical devices ###
+
+Interrupts from physical devices are delivered using native methods, this is
+done in order to take advantage of new hardware assisted virtualization
+functions, like posted interrupts. This implies that PVHv2 guests with physical
+devices will also have the necessary interrupt controllers in order to manage
+the delivery of interrupts from those devices, using the same interfaces that
+are available on native hardware.
+
+### Interrupts from paravirtualized devices ###
+
+Interrupts from paravirtualized devices are delivered using event channels, see
+[Event Channel Internals][event_channels] for more detailed information about
+event channels. Delivery of those interrupts can be configured in the same way
+as HVM guests, check xen/include/public/hvm/params.h and
+xen/include/public/hvm/hvm_op.h for more information about available delivery
+methods.

diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index 0f7c310d28bb4631166353463f7715fdec469d44..6499caaa7c8cd70611e1077daa205a3a36935f76 100644 (file)
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -86,6 +86,8 @@ static long hvm_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
     case PHYSDEVOP_eoi:
     case PHYSDEVOP_irq_status_query:
     case PHYSDEVOP_get_free_pirq:
+        if ( !has_pirq(curr->domain) && !is_pvh_vcpu(curr) )
+            return -ENOSYS;
         break;
     }
 

diff --git a/xen/arch/x86/physdev.c b/xen/arch/x86/physdev.c
index 018f8b5570e609d81b234afbfc59a66035112502..fc45bfb7e62e16f7cdcbbd139bade3e4dc553bc5 100644 (file)
--- a/xen/arch/x86/physdev.c
+++ b/xen/arch/x86/physdev.c
@@ -93,7 +93,7 @@ int physdev_map_pirq(domid_t domid, int type, int *index, int *pirq_p,
     int pirq, irq, ret = 0;
     void *map_data = NULL;
 
-    if ( domid == DOMID_SELF && is_hvm_domain(d) )
+    if ( domid == DOMID_SELF && is_hvm_domain(d) && has_pirq(d) )
     {
         /*
          * Only makes sense for vector-based callback, else HVM-IRQ logic
@@ -264,7 +264,7 @@ int physdev_unmap_pirq(domid_t domid, int pirq)
     if ( ret )
         goto free_domain;
 
-    if ( is_hvm_domain(d) )
+    if ( is_hvm_domain(d) && has_pirq(d) )
     {
         spin_lock(&d->event_lock);
         if ( domain_pirq_to_emuirq(d, pirq) != IRQ_UNBOUND )

diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index d0edb13d4bb273a845a8bac3a572d006f8f50358..4b87c60845c7499cbeccb9f478cbacc9cd80d08a 100644 (file)
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -332,7 +332,7 @@ DO(xen_version)(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
             case guest_type_hvm:
                 fi.submap |= (1U << XENFEAT_hvm_safe_pvclock) |
                              (1U << XENFEAT_hvm_callback_vector) |
-                             (1U << XENFEAT_hvm_pirqs);
+                             (has_pirq(d) ? (1U << XENFEAT_hvm_pirqs) : 0);
                 break;
             }
 #endif

diff --git a/xen/include/asm-x86/domain.h b/xen/include/asm-x86/domain.h
index 09232bfc4ba9a0f0ca4a443f9764a0f767ef88cd..d8749df4eba94569e7ea6618aba1ebfe5ad6c57f 100644 (file)
--- a/xen/include/asm-x86/domain.h
+++ b/xen/include/asm-x86/domain.h
@@ -422,6 +422,8 @@ struct arch_domain
 #define has_vvga(d)        (!!((d)->arch.emulation_flags & XEN_X86_EMU_VGA))
 #define has_viommu(d)      (!!((d)->arch.emulation_flags & XEN_X86_EMU_IOMMU))
 #define has_vpit(d)        (!!((d)->arch.emulation_flags & XEN_X86_EMU_PIT))
+#define has_pirq(d)        (!!((d)->arch.emulation_flags & \
+                            XEN_X86_EMU_USE_PIRQ))
 
 #define has_arch_pdevs(d)    (!list_empty(&(d)->arch.pdev_list))
 

diff --git a/xen/include/public/arch-x86/xen.h b/xen/include/public/arch-x86/xen.h
index 363c8cc7eddce1ed3a9146e55088137c8fd3be41..73c829ae3fba50370bb28c14e4de85f7024e1859 100644 (file)
--- a/xen/include/public/arch-x86/xen.h
+++ b/xen/include/public/arch-x86/xen.h
@@ -293,12 +293,14 @@ struct xen_arch_domainconfig {
 #define XEN_X86_EMU_IOMMU           (1U<<_XEN_X86_EMU_IOMMU)
 #define _XEN_X86_EMU_PIT            8
 #define XEN_X86_EMU_PIT             (1U<<_XEN_X86_EMU_PIT)
+#define _XEN_X86_EMU_USE_PIRQ       9
+#define XEN_X86_EMU_USE_PIRQ        (1U<<_XEN_X86_EMU_USE_PIRQ)
 
 #define XEN_X86_EMU_ALL             (XEN_X86_EMU_LAPIC | XEN_X86_EMU_HPET |  \
                                      XEN_X86_EMU_PM | XEN_X86_EMU_RTC |      \
                                      XEN_X86_EMU_IOAPIC | XEN_X86_EMU_PIC |  \
                                      XEN_X86_EMU_VGA | XEN_X86_EMU_IOMMU |   \
-                                     XEN_X86_EMU_PIT)
+                                     XEN_X86_EMU_PIT | XEN_X86_EMU_USE_PIRQ)
     uint32_t emulation_flags;
 };