1 files changed, 76 insertions, 0 deletions
diff --git a/system/xen/xsa/xsa196-0002-x86-svm-Fix-injection-of-software-interrupts.patch b/system/xen/xsa/xsa196-0002-x86-svm-Fix-injection-of-software-interrupts.patch
new file mode 100644
index 0000000000..26580ff809
--- /dev/null
+++ b/system/xen/xsa/xsa196-0002-x86-svm-Fix-injection-of-software-interrupts.patch
@@ -0,0 +1,76 @@
+From: Andrew Cooper <andrew.cooper3@citrix.com>
+Subject: x86/svm: Fix injection of software interrupts
+
+The non-NextRip logic in c/s 36ebf14eb "x86/emulate: support for emulating
+software event injection" was based on an older version of the AMD software
+manual.  The manual was later corrected, following findings from that series.
+
+I took the original wording of "not supported without NextRIP" to mean that
+X86_EVENTTYPE_SW_INTERRUPT was not eligible for use.  It turns out that this
+is not the case, and the new wording is clearer on the matter.
+
+Despite testing the original patch series on non-NRip hardware, the
+swint-emulation XTF test case focuses on the debug vectors; it never ended up
+executing an `int $n` instruction for a vector which wasn't also an exception.
+
+During a vmentry, the use of X86_EVENTTYPE_HW_EXCEPTION comes with a vector
+check to ensure that it is only used with exception vectors.  Xen's use of
+X86_EVENTTYPE_HW_EXCEPTION for `int $n` injection has always been buggy on AMD
+hardware.
+
+Fix this by always using X86_EVENTTYPE_SW_INTERRUPT.
+
+Print and decode the eventinj information in svm_vmcb_dump(), as it has
+several invalid combinations which cause vmentry failures.
+
+This is part of XSA-196.
+
+Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
+Reviewed-by: Jan Beulich <jbeulich@suse.com>
+---
+ xen/arch/x86/hvm/svm/svm.c      | 13 +++++--------
+ xen/arch/x86/hvm/svm/svmdebug.c |  4 ++++
+ 2 files changed, 9 insertions(+), 8 deletions(-)
+
+diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
+index 4391744..76efc3e 100644
+--- a/xen/arch/x86/hvm/svm/svm.c
++++ b/xen/arch/x86/hvm/svm/svm.c
+@@ -1231,17 +1231,14 @@ static void svm_inject_trap(const struct hvm_trap *trap)
+     {
+     case X86_EVENTTYPE_SW_INTERRUPT: /* int $n */
+         /*
+-         * Injection type 4 (software interrupt) is only supported with
+-         * NextRIP support.  Without NextRIP, the emulator will have performed
+-         * DPL and presence checks for us.
++         * Software interrupts (type 4) cannot be properly injected if the
++         * processor doesn't support NextRIP.  Without NextRIP, the emulator
++         * will have performed DPL and presence checks for us, and will have
++         * moved eip forward if appropriate.
+          */
+         if ( cpu_has_svm_nrips )
+-        {
+             vmcb->nextrip = regs->eip + _trap.insn_len;
+-            event.fields.type = X86_EVENTTYPE_SW_INTERRUPT;
+-        }
+-        else
+-            event.fields.type = X86_EVENTTYPE_HW_EXCEPTION;
++        event.fields.type = X86_EVENTTYPE_SW_INTERRUPT;
+         break;
+ 
+     case X86_EVENTTYPE_PRI_SW_EXCEPTION: /* icebp */
+diff --git a/xen/arch/x86/hvm/svm/svmdebug.c b/xen/arch/x86/hvm/svm/svmdebug.c
+index ded5d19..f93dfed 100644
+--- a/xen/arch/x86/hvm/svm/svmdebug.c
++++ b/xen/arch/x86/hvm/svm/svmdebug.c
+@@ -48,6 +48,10 @@ void svm_vmcb_dump(const char *from, struct vmcb_struct *vmcb)
+            vmcb->tlb_control,
+            (unsigned long long)vmcb->_vintr.bytes,
+            (unsigned long long)vmcb->interrupt_shadow);
++    printk("eventinj %016"PRIx64", valid? %d, ec? %d, type %u, vector %#x\n",
++           vmcb->eventinj.bytes, vmcb->eventinj.fields.v,
++           vmcb->eventinj.fields.ev, vmcb->eventinj.fields.type,
++           vmcb->eventinj.fields.vector);
+     printk("exitcode = %#Lx exitintinfo = %#Lx\n",
+            (unsigned long long)vmcb->exitcode,
+            (unsigned long long)vmcb->exitintinfo.bytes);