From: Sean Christopherson <seanjc@google.com>
To: Xiaoyao Li <xiaoyao.li@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Chao Gao <chao.gao@intel.com>, Xin Li <xin@zytor.com>,
Yosry Ahmed <yosry.ahmed@linux.dev>
Subject: Re: [PATCH v3 3/4] KVM: nVMX: Disallow access to vmcs12 fields that aren't supported by "hardware"
Date: Fri, 9 Jan 2026 06:44:29 -0800 [thread overview]
Message-ID: <aWEUTQeNXugBYAZA@google.com> (raw)
In-Reply-To: <288eaa68-7d4d-4c1b-ae70-419554d1d8f2@intel.com>
On Fri, Jan 09, 2026, Xiaoyao Li wrote:
> On 1/9/2026 12:15 PM, Sean Christopherson wrote:
> > diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> > index 61113ead3d7b..ac7a17560c8f 100644
> > --- a/arch/x86/kvm/vmx/nested.c
> > +++ b/arch/x86/kvm/vmx/nested.c
> > @@ -111,6 +111,9 @@ static void init_vmcs_shadow_fields(void)
> > field <= GUEST_TR_AR_BYTES,
> > "Update vmcs12_write_any() to drop reserved bits from AR_BYTES");
> > + if (get_vmcs12_field_offset(field) < 0)
> > + continue;
> > +
>
> why shadow_read_only_fields[] doesn't need such guard?
>
> IIUC, copy_vmcs12_to_shadow() will VMWRITE shadowed readonly field even if
> it doesn't exist on the hardware?
Because I fixated on the existing checks and didn't look at the first for-loop.
This time around I'll test by hacking in shadowed fields arbitrary shadow fields.
next prev parent reply other threads:[~2026-01-09 14:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-09 4:15 [PATCH v3 0/4] KVM: nVMX: Disallow access to vmcs12 fields that aren't supported by "hardware" Sean Christopherson
2026-01-09 4:15 ` [PATCH v3 1/4] KVM: nVMX: Setup VMX MSRs on loading CPU during nested_vmx_hardware_setup() Sean Christopherson
2026-01-09 11:24 ` Xiaoyao Li
2026-01-09 4:15 ` [PATCH v3 2/4] KVM: VMX: Add a wrapper around ROL16() to get a vmcs12 from a field encoding Sean Christopherson
2026-01-09 11:34 ` Xiaoyao Li
2026-01-09 4:15 ` [PATCH v3 3/4] KVM: nVMX: Disallow access to vmcs12 fields that aren't supported by "hardware" Sean Christopherson
2026-01-09 14:08 ` Xiaoyao Li
2026-01-09 14:44 ` Sean Christopherson [this message]
2026-01-09 15:17 ` Sean Christopherson
2026-01-09 4:15 ` [PATCH v3 4/4] KVM: nVMX: Remove explicit filtering of GUEST_INTR_STATUS from shadow VMCS fields Sean Christopherson
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