On 4/23/2025 7:46 PM, Zhao Liu wrote:
Per SDM, 0x80000005 leaf is reserved for Intel CPU, and its current
"assert" check blocks adding new cache model for non-AMD CPUs.
Therefore, check the vendor and encode this leaf as all-0 for Intel
CPU. And since Zhaoxin mostly follows Intel behavior, apply the vendor
check for Zhaoxin as well.
Note, for !vendor_cpuid_only case, non-AMD CPU would get the wrong
information, i.e., get AMD's cache model for Intel or Zhaoxin CPUs.
For this case, there is no need to tweak for non-AMD CPUs, because
vendor_cpuid_only has been turned on by default since PC machine v6.1.
Signed-off-by: Zhao Liu <zhao1....@intel.com>
---
target/i386/cpu.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 1b64ceaaba46..8fdafa8aedaf 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -7248,11 +7248,23 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
uint32_t count,
*edx = env->cpuid_model[(index - 0x80000002) * 4 + 3];
break;
case 0x80000005:
- /* cache info (L1 cache) */
- if (cpu->cache_info_passthrough) {
+ /*
+ * cache info (L1 cache)
+ *
+ * For !vendor_cpuid_only case, non-AMD CPU would get the wrong
+ * information, i.e., get AMD's cache model. It doesn't matter,
+ * vendor_cpuid_only has been turned on by default since
+ * PC machine v6.1.
+ */
We need to define a new compat property for it other than
vendor_cpuid_only, for 10.1.
I proposed some change to leaf FEAT_8000_0001_EDX[1], and I was told by
Paolo (privately) that vendor_cpuid_only doesn't suffice.
On Fri, Oct 11, 2024 at 6:22 PM Xiaoyao Li <xiaoyao...@intel.com> wrote:
>
> On 10/11/2024 11:30 PM, Paolo Bonzini wrote:
> > On Fri, Oct 11, 2024 at 4:55 PM Xiaoyao Li <xiaoyao...@intel.com>
wrote:
> >>
> >> I think patch 8 is also a general issue> Without it, the
> >> CPUID_EXT2_AMD_ALIASES bits are exposed to Intel VMs which are
> >> reserved bits for Intel.
> >
> > Yes but you'd have to add compat properties for these. If you can do
> > it for TDX only, that's easier.
>
> Does vendor_cpuid_only suffice?
Unfortunately not, because it is turned off only for <=6.0 machine
types. Here you'd have to turn it off for <=9.1 machine types.
[1]
https://lore.kernel.org/qemu-devel/20240814075431.339209-9-xiaoyao...@intel.com/
+ if (cpu->vendor_cpuid_only &&
+ (IS_INTEL_CPU(env) || IS_ZHAOXIN_CPU(env))) {
+ *eax = *ebx = *ecx = *edx = 0;
+ break;
+ } else if (cpu->cache_info_passthrough) {
x86_cpu_get_cache_cpuid(index, 0, eax, ebx, ecx, edx);
break;
}
+
*eax = (L1_DTLB_2M_ASSOC << 24) | (L1_DTLB_2M_ENTRIES << 16) |
(L1_ITLB_2M_ASSOC << 8) | (L1_ITLB_2M_ENTRIES);
*ebx = (L1_DTLB_4K_ASSOC << 24) | (L1_DTLB_4K_ENTRIES << 16) |
