[Xen-changelog] [xen stable-4.9] VMX: fix vmx_handle_eoi()

[patchbot@xxxxxxx]

commit fd6ab0e87edb2cbbd79f4915aebf0849969711f5
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Feb 1 11:59:52 2019 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Feb 1 11:59:52 2019 +0100

    VMX: fix vmx_handle_eoi()
    
    In commit 303066fdb1e ("VMX: fix interaction of APIC-V and Viridian
    emulation") I screwed up: Instead of clearing SVI, other ISR bits
    should be taken into account.
    
    Introduce a new helper set_svi(), split out of vmx_process_isr(), and
    use it also from vmx_handle_eoi().
    
    Following the problems in vmx_intr_assist() (see the still present big
    block of debugging code there) also warn (once) if EOI'd vector and
    original SVI don't match.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Chao Gao <chao.gao@xxxxxxxxx>
    Acked-by: Kevin Tian <kevin.tian@xxxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    master commit: 45cb9a4123b5550eb1f84846fe5482acae1c13a3
    master date: 2018-11-02 12:15:33 +0100
---
 xen/arch/x86/hvm/vlapic.c     |  2 +-
 xen/arch/x86/hvm/vmx/vmx.c    | 28 ++++++++++++++++++----------
 xen/include/asm-x86/hvm/hvm.h |  2 +-
 3 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/xen/arch/x86/hvm/vlapic.c b/xen/arch/x86/hvm/vlapic.c
index 350acbf21c..f5e23da2cc 100644
--- a/xen/arch/x86/hvm/vlapic.c
+++ b/xen/arch/x86/hvm/vlapic.c
@@ -415,7 +415,7 @@ void vlapic_EOI_set(struct vlapic *vlapic)
     vlapic_clear_vector(vector, &vlapic->regs->data[APIC_ISR]);
 
     if ( hvm_funcs.handle_eoi )
-        hvm_funcs.handle_eoi(vector);
+        hvm_funcs.handle_eoi(vector, vlapic_find_highest_isr(vlapic));
 
     vlapic_handle_EOI(vlapic, vector);
 }
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index bc8f566b9c..9f97f388c9 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -1999,17 +1999,14 @@ static int vmx_virtual_intr_delivery_enabled(void)
     return cpu_has_vmx_virtual_intr_delivery;
 }
 
-static void vmx_process_isr(int isr, struct vcpu *v)
+static u8 set_svi(int isr)
 {
     unsigned long status;
     u8 old;
-    unsigned int i;
-    const struct vlapic *vlapic = vcpu_vlapic(v);
 
     if ( isr < 0 )
         isr = 0;
 
-    vmx_vmcs_enter(v);
     __vmread(GUEST_INTR_STATUS, &status);
     old = status >> VMX_GUEST_INTR_STATUS_SVI_OFFSET;
     if ( isr != old )
@@ -2019,6 +2016,18 @@ static void vmx_process_isr(int isr, struct vcpu *v)
         __vmwrite(GUEST_INTR_STATUS, status);
     }
 
+    return old;
+}
+
+static void vmx_process_isr(int isr, struct vcpu *v)
+{
+    unsigned int i;
+    const struct vlapic *vlapic = vcpu_vlapic(v);
+
+    vmx_vmcs_enter(v);
+
+    set_svi(isr);
+
     /*
      * Theoretically, only level triggered interrupts can have their
      * corresponding bits set in the eoi exit bitmap. That is, the bits
@@ -2164,14 +2173,13 @@ static void vmx_sync_pir_to_irr(struct vcpu *v)
         vlapic_set_vector(i, &vlapic->regs->data[APIC_IRR]);
 }
 
-static void vmx_handle_eoi(u8 vector)
+static void vmx_handle_eoi(uint8_t vector, int isr)
 {
-    unsigned long status;
+    uint8_t old_svi = set_svi(isr);
+    static bool warned;
 
-    /* We need to clear the SVI field. */
-    __vmread(GUEST_INTR_STATUS, &status);
-    status &= VMX_GUEST_INTR_STATUS_SUBFIELD_BITMASK;
-    __vmwrite(GUEST_INTR_STATUS, status);
+    if ( vector != old_svi && !test_and_set_bool(warned) )
+        printk(XENLOG_WARNING "EOI for %02x but SVI=%02x\n", vector, old_svi);
 }
 
 static void vmx_enable_msr_interception(struct domain *d, uint32_t msr)
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 6a65fb414d..5c4ff900c3 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -195,7 +195,7 @@ struct hvm_function_table {
     void (*process_isr)(int isr, struct vcpu *v);
     void (*deliver_posted_intr)(struct vcpu *v, u8 vector);
     void (*sync_pir_to_irr)(struct vcpu *v);
-    void (*handle_eoi)(u8 vector);
+    void (*handle_eoi)(uint8_t vector, int isr);
 
     /*Walk nested p2m  */
     int (*nhvm_hap_walk_L1_p2m)(struct vcpu *v, paddr_t L2_gpa,
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.9

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