[Xen-devel] [PATCH v2 3/4] x86/nvmx: split updating RVI from SVI in nvmx_update_apicv

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

Updating SVI is required when an interrupt has been injected using the
Ack on exit VMEXIT feature, so that the in service interrupt in the
GUEST_INTR_STATUS matches the vector that is signaled in
VM_EXIT_INTR_INFO.

Updating RVI however is not tied to the Ack on exit feature, as it
signals the next vector to be injected, and hence should always be
updated to the next pending vector, regardless of whether Ack on exit
is enabled.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vvmx.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index 1753005c91..8431c912a1 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1384,26 +1384,38 @@ static void nvmx_update_apicv(struct vcpu *v)
     struct nestedvmx *nvmx = &vcpu_2_nvmx(v);
     unsigned long reason = get_vvmcs(v, VM_EXIT_REASON);
     unsigned long intr_info = get_vvmcs(v, VM_EXIT_INTR_INFO);
+    int rvi;
 
     if ( reason == EXIT_REASON_EXTERNAL_INTERRUPT &&
          nvmx->intr.source == hvm_intsrc_lapic &&
          (intr_info & INTR_INFO_VALID_MASK) )
     {
         uint16_t status;
-        uint32_t rvi, ppr;
-        uint32_t vector = intr_info & 0xff;
+        uint32_t ppr;
+        unsigned int vector = intr_info & INTR_INFO_VECTOR_MASK;
         struct vlapic *vlapic = vcpu_vlapic(v);
 
+        /*
+         * Update SVI to record the currently in service interrupt that's
+         * signaled in EXIT_INTR_INFO.
+         */
         vlapic_ack_pending_irq(v, vector, 1);
 
         ppr = vlapic_set_ppr(vlapic);
         WARN_ON((ppr & 0xf0) != (vector & 0xf0));
 
         status = vector << VMX_GUEST_INTR_STATUS_SVI_OFFSET;
-        rvi = vlapic_has_pending_irq(v);
-        if ( rvi != -1 )
-            status |= rvi & VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
+        __vmwrite(GUEST_INTR_STATUS, status);
+    }
+
+    rvi = vlapic_has_pending_irq(v);
+    if ( rvi != -1 )
+    {
+        unsigned long status;
 
+        __vmread(GUEST_INTR_STATUS, &status);
+        status &= ~VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
+        status |= rvi & VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
         __vmwrite(GUEST_INTR_STATUS, status);
     }
 }
-- 
2.26.0