On 1/17/2024 1:31 PM, Yuan Yao wrote:
On Wed, Jan 17, 2024 at 09:58:40AM +0800, Yang, Weijiang wrote:
On 1/17/2024 9:41 AM, Yang, Weijiang wrote:
On 1/15/2024 5:58 PM, Yuan Yao wrote:
On Thu, Dec 21, 2023 at 09:02:35AM -0500, Yang Weijiang wrote:
[...]
Looks this leading to MSR_IA32_INT_SSP_TAB not intercepted
after below steps:
Step 1. User space set cpuid w/ X86_FEATURE_LM, w/ SHSTK.
Step 2. User space set cpuid w/o X86_FEATURE_LM, w/o SHSTK.
Then MSR_IA32_INT_SSP_TAB won't be intercepted even w/o SHSTK
on guest cpuid, will this lead to inconsistency when do
rdmsr(MSR_IA32_INT_SSP_TAB) from guest in this scenario ?
Yes, theoretically it's possible, how about changing it as below?
vmx_set_intercept_for_msr(vcpu, MSR_IA32_INT_SSP_TAB,
MSR_TYPE_RW,
incpt | !guest_cpuid_has(vcpu, X86_FEATURE_LM));
Oops, should be : incpt || !guest_cpuid_has(vcpu, X86_FEATURE_LM)
It means guest cpuid:
"has X86_FEATURE_SHSTK" + "doesn't have X86_FEATURE_LM"
No, this is invalid within this series. With patch 21 to prevent SHSTK in
32-bit guest, I think the check of LM here can be omitted.
then
vmx_set_intercept_for_msr(vcpu, MSR_IA32_INT_SSP_TAB, MSR_TYPE_RW, incpt); is OK.
not sure this is valid combination or not.
If yes it's ok, else just relies on incpt is enough ?
