Re: [PATCH v3 2/3] i386: Explicitly ignore unsupported BUS_MCEERR_AO MCE on AMD guest

[Gupta, Pankaj]

On 9/6/2023 10:53 PM, John Allen wrote:

From: William Roche <william.ro...@oracle.com>

AMD guests can't currently deal with BUS_MCEERR_AO MCE injection
as it panics the VM kernel. We filter this event and provide a
warning message.

Signed-off-by: William Roche <william.ro...@oracle.com>
---
v3:
   - New patch
---
  target/i386/kvm/kvm.c | 13 ++++++++++---
  1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 5fce74aac5..4d42d3ed4c 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -604,6 +604,10 @@ static void kvm_mce_inject(X86CPU *cpu, hwaddr paddr, int 
code)
              mcg_status |= MCG_STATUS_RIPV;
          }
      } else {
+        if (code == BUS_MCEERR_AO) {
+            /* XXX we don't support BUS_MCEERR_AO injection on AMD yet */
+            return;
+        }
          mcg_status |= MCG_STATUS_EIPV | MCG_STATUS_RIPV;
      }

@@ -655,7 +659,9 @@ void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr)

          if (ram_addr != RAM_ADDR_INVALID &&
              kvm_physical_memory_addr_from_host(c->kvm_state, addr, &paddr)) {
              kvm_hwpoison_page_add(ram_addr);
-            kvm_mce_inject(cpu, paddr, code);
+            if (!IS_AMD_CPU(env) || code != BUS_MCEERR_AO) {

Isn't the 'optional' case we already handle inside kvm_mce_inject()?
So this check seems repetitive to me.

Thanks,
Pankaj

+                kvm_mce_inject(cpu, paddr, code);
+            }

/*

               * Use different logging severity based on error type.
@@ -668,8 +674,9 @@ void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void 
*addr)
                      addr, paddr, "BUS_MCEERR_AR");
              } else {
                   warn_report("Guest MCE Memory Error at QEMU addr %p and "
-                     "GUEST addr 0x%" HWADDR_PRIx " of type %s injected",
-                     addr, paddr, "BUS_MCEERR_AO");
+                     "GUEST addr 0x%" HWADDR_PRIx " of type %s %s",
+                     addr, paddr, "BUS_MCEERR_AO",
+                     IS_AMD_CPU(env) ? "ignored on AMD guest" : "injected");
              }

return;