Re: [PATCH v6 13/60] i386/tdx: Validate TD attributes

Daniel P. Berrangé
2024-11-05T11:55:13Z

On Tue, Nov 05, 2024 at 07:53:57PM +0800, Xiaoyao Li wrote:
> On 11/5/2024 6:36 PM, Daniel P. Berrangé wrote:
> > On Tue, Nov 05, 2024 at 01:23:21AM -0500, Xiaoyao Li wrote:
> > > Validate TD attributes with tdx_caps that fixed-0 bits must be zero and
> > > fixed-1 bits must be set.
> > >
> > > Besides, sanity check the attribute bits that have not been supported by
> > > QEMU yet. e.g., debug bit, it will be allowed in the future when debug
> > > TD support lands in QEMU.
> > >
> > > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> > > Acked-by: Gerd Hoffmann <kraxel@redhat.com>
> > >
> > > ---
> > > Changes in v3:
> > > - using error_setg() for error report; (Daniel)
> > > ---
> > > target/i386/kvm/tdx.c | 28 ++++++++++++++++++++++++++--
> > > 1 file changed, 26 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
> > > index 6cf81f788fe0..5a9ce2ada89d 100644
> > > --- a/target/i386/kvm/tdx.c
> > > +++ b/target/i386/kvm/tdx.c
> > > @@ -20,6 +20,7 @@
> > > #include "kvm_i386.h"
> > > #include "tdx.h"
> > > +#define TDX_TD_ATTRIBUTES_DEBUG BIT_ULL(0)
> > > #define TDX_TD_ATTRIBUTES_SEPT_VE_DISABLE BIT_ULL(28)
> > > #define TDX_TD_ATTRIBUTES_PKS BIT_ULL(30)
> > > #define TDX_TD_ATTRIBUTES_PERFMON BIT_ULL(63)
> > > @@ -141,13 +142,33 @@ static int tdx_kvm_type(X86ConfidentialGuest *cg)
> > > return KVM_X86_TDX_VM;
> > > }
> > > -static void setup_td_guest_attributes(X86CPU *x86cpu)
> > > +static int tdx_validate_attributes(TdxGuest *tdx, Error **errp)
> > > +{
> > > + if ((tdx->attributes & ~tdx_caps->supported_attrs)) {
> > > + error_setg(errp, "Invalid attributes 0x%lx for TDX VM "
> > > + "(supported: 0x%llx)",
> > > + tdx->attributes, tdx_caps->supported_attrs);
> > > + return -1;
> >
> > Minor whitespace accident, with indentation too deep.
>
> Good catch!
>
> btw, how did you catch it? any tool like checkpatch.pl or just by your eyes?

Nah, I just notice the mis-alignment when reading the patches.

>
> > > + }
> > > +
> > > + if (tdx->attributes & TDX_TD_ATTRIBUTES_DEBUG) {
> > > + error_setg(errp, "Current QEMU doesn't support attributes.debug[bit 0] "
> > > + "for TDX VM");
> > > + return -1;
> > > + }
> > > +
> > > + return 0;
> > > +}

With regards,
Daniel
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