[Xen-changelog] [xen staging] x86/nvmx: split updating RVI from SVI in nvmx_update_apicv

[patchbot@xxxxxxx]

commit 25df013e7ab27c95044655fbc188ea9810e471be
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Fri Mar 27 13:45:58 2020 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Fri Mar 27 13:14:54 2020 +0000

    x86/nvmx: split updating RVI from SVI in nvmx_update_apicv
    
    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.
    
    When not using the Ack on exit feature preserve the previous vector in
    SVI, so that it's not lost when RVI is updated to contain the pending
    vector to inject.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vvmx.c | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index 1753005c91..d63f417f9c 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1384,28 +1384,43 @@ 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);
+    unsigned long status;
+    int rvi;
 
-    if ( reason == EXIT_REASON_EXTERNAL_INTERRUPT &&
-         nvmx->intr.source == hvm_intsrc_lapic &&
-         (intr_info & INTR_INFO_VALID_MASK) )
+    if ( reason != EXIT_REASON_EXTERNAL_INTERRUPT ||
+         nvmx->intr.source != hvm_intsrc_lapic )
+        return;
+
+    if ( 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 current 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;
+    }
+    else
+       /* Keep previous SVI if there's any. */
+       __vmread(GUEST_INTR_STATUS, &status);
 
-        __vmwrite(GUEST_INTR_STATUS, status);
+    rvi = vlapic_has_pending_irq(v);
+    if ( rvi != -1 )
+    {
+        status &= ~VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
+        status |= rvi & VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
     }
+
+    if ( status )
+        __vmwrite(GUEST_INTR_STATUS, status);
 }
 
 static void virtual_vmexit(struct cpu_user_regs *regs)
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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