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    SubjectRe: [PATCHv7 02/30] x86/tdx: Provide common base for SEAMCALL and TDCALL C wrappers
    On Sat, Mar 19, 2022 at 03:48:11PM +0100, Borislav Petkov wrote:
    > On Fri, Mar 18, 2022 at 06:30:20PM +0300, Kirill A. Shutemov wrote:
    > > Secure Arbitration Mode (SEAM) is an extension of VMX architecture. It
    > > defines a new VMX root operation (SEAM VMX root) and a new VMX non-root
    > > operation (SEAM VMX non-root) which are both isolated from the legacy
    > > VMX operation where the host kernel runs.
    > >
    > > A CPU-attested software module (called 'TDX module') runs in SEAM VMX
    > > root to manage and protect VMs running in SEAM VMX non-root. SEAM VMX
    > > root is also used to host another CPU-attested software module (called
    > > 'P-SEAMLDR') to load and update the TDX module.
    > >
    > > Host kernel transits to either P-SEAMLDR or TDX module via the new
    > > SEAMCALL instruction, which is essentially a VMExit from VMX root mode
    > > to SEAM VMX root mode. SEAMCALLs are leaf functions defined by
    > > P-SEAMLDR and TDX module around the new SEAMCALL instruction.
    > >
    > > A guest kernel can also communicate with TDX module via TDCALL
    > > instruction.
    > >
    > > TDCALLs and SEAMCALLs use an ABI different from the x86-64 system-v ABI.
    > > RAX is used to carry both the SEAMCALL leaf function number (input) and
    > > the completion status (output). Additional GPRs (RCX, RDX, R8-R11) may
    > > be further used as both input and output operands in individual leaf.
    > >
    > > TDCALL and SEAMCALL share the same ABI and require the largely same
    > > code to pass down arguments and retrieve results.
    > >
    > > Define an assembly macro that can be used to implement C wrapper for
    > > both TDCALL and SEAMCALL.
    > >
    > > Suggested-by: Thomas Gleixner <tglx@linutronix.de>
    > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
    > > Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
    > > Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
    > > ---
    > > TDCALL wrapper will be implemented using the macro later in the series.
    > > SEAMCALL wrapper is out-of-scope for the series and will be implemented
    > > as part of TDX host enabling.
    > > ---
    > > arch/x86/include/asm/tdx.h | 28 ++++++++++
    > > arch/x86/kernel/asm-offsets.c | 9 ++++
    > > arch/x86/virt/vmx/tdx/tdxcall.S | 94 +++++++++++++++++++++++++++++++++
    > > 3 files changed, 131 insertions(+)
    > > create mode 100644 arch/x86/virt/vmx/tdx/tdxcall.S
    >
    > Instead of hurrying to send the set again two days after the v6 one -
    >
    > [ I frankly wonder why you're even in such a hurry - it seems people
    > believe that hammering out the patches constantly would somehow get them
    > upstreamed faster :-\ ]
    >
    > - you should rather apply more diligence and take care of working in all
    > the comments from last review:
    >
    > https://lore.kernel.org/r/87lex9321l.ffs@tglx

    My bad.

    I clearly remember addressing these. But I lost it somehow, I donno.

    Will send v7.1.

    --
    Kirill A. Shutemov

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