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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: x86@kernel.org, Joerg Roedel <jroedel@suse.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Kees Cook <keescook@chromium.org>,
	Arvind Sankar <nivedita@alum.mit.edu>,
	Martin Radev <martin.b.radev@gmail.com>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] x86/boot/compressed/64: Introduce sev_status
Date: Mon, 19 Oct 2020 18:08:01 -0700	[thread overview]
Message-ID: <20201020010801.GA24746@linux.intel.com> (raw)
In-Reply-To: <20201020005925.GA24596@linux.intel.com>

On Mon, Oct 19, 2020 at 05:59:25PM -0700, Sean Christopherson wrote:
> On Mon, Oct 19, 2020 at 05:11:17PM +0200, Joerg Roedel wrote:
> > From: Joerg Roedel <jroedel@suse.de>
> > 
> > Introduce sev_status and initialize it together with sme_me_mask to have
> > an indicator which SEV features are enabled.
> > 
> > Signed-off-by: Joerg Roedel <jroedel@suse.de>
> > ---
> >  arch/x86/boot/compressed/mem_encrypt.S | 14 +++++++++++++-
> >  1 file changed, 13 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S
> > index dd07e7b41b11..0effd58f0095 100644
> > --- a/arch/x86/boot/compressed/mem_encrypt.S
> > +++ b/arch/x86/boot/compressed/mem_encrypt.S
> > @@ -71,6 +71,8 @@ SYM_FUNC_END(get_sev_encryption_bit)
> >  SYM_FUNC_START(set_sev_encryption_mask)
> >  #ifdef CONFIG_AMD_MEM_ENCRYPT
> >  	push	%rbp
> > +	push	%rax
> > +	push	%rcx
> 
> There's no need to save/restore RAX and RCX, they are callee save.  This
> function is only called from C, so I doubt it's using a custom ABI.

Gah, *caller* save.  Feedback stands, my English notwithstanding.

  reply	other threads:[~2020-10-20  1:08 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-19 15:11 [PATCH 0/5] x86/sev-es: Mitigate some HV attack vectors Joerg Roedel
2020-10-19 15:11 ` [PATCH 1/5] x86/boot/compressed/64: Introduce sev_status Joerg Roedel
2020-10-20  0:59   ` Sean Christopherson
2020-10-20  1:08     ` Sean Christopherson [this message]
2020-10-20  9:55     ` Joerg Roedel
2020-10-19 15:11 ` [PATCH 2/5] x86/boot/compressed/64: Add CPUID sanity check to early #VC handler Joerg Roedel
2020-10-19 15:11 ` [PATCH 3/5] x86/boot/compressed/64: Check SEV encryption in 64-bit boot-path Joerg Roedel
2020-10-19 17:00   ` Arvind Sankar
2020-10-19 17:54     ` Arvind Sankar
2020-10-19 20:39       ` Joerg Roedel
2020-10-19 21:31         ` Arvind Sankar
2020-10-20  8:59           ` Joerg Roedel
2020-10-20 14:33             ` Arvind Sankar
2020-10-20 15:44               ` Joerg Roedel
2020-10-19 20:33     ` Joerg Roedel
2020-10-19 21:22       ` Arvind Sankar
2020-10-20  9:41         ` Joerg Roedel
2020-10-19 15:11 ` [PATCH 4/5] x86/head/64: Check SEV encryption before switching to kernel page-table Joerg Roedel
2020-10-19 15:11 ` [PATCH 5/5] x86/sev-es: Do not support MMIO to/from encrypted memory Joerg Roedel

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