From: Michael Roth <michael.roth@amd.com>
To: Tianyu Lan <ltykernel@gmail.com>
Cc: <luto@kernel.org>, <tglx@linutronix.de>, <mingo@redhat.com>,
<bp@alien8.de>, <dave.hansen@linux.intel.com>, <x86@kernel.org>,
<hpa@zytor.com>, <seanjc@google.com>, <pbonzini@redhat.com>,
<jgross@suse.com>, <tiala@microsoft.com>, <kirill@shutemov.name>,
<jiangshan.ljs@antgroup.com>, <peterz@infradead.org>,
<ashish.kalra@amd.com>, <srutherford@google.com>,
<akpm@linux-foundation.org>, <anshuman.khandual@arm.com>,
<pawan.kumar.gupta@linux.intel.com>, <adrian.hunter@intel.com>,
<daniel.sneddon@linux.intel.com>,
<alexander.shishkin@linux.intel.com>, <sandipan.das@amd.com>,
<ray.huang@amd.com>, <brijesh.singh@amd.com>,
<thomas.lendacky@amd.com>, <venu.busireddy@oracle.com>,
<sterritt@google.com>, <tony.luck@intel.com>,
<samitolvanen@google.com>, <fenghua.yu@intel.com>,
<linux-kernel@vger.kernel.org>, <kvm@vger.kernel.org>,
<linux-hyperv@vger.kernel.org>, <linux-arch@vger.kernel.org>
Subject: Re: [RFC PATCH 01/17] x86/boot: Check boot param's cc_blob_address for direct boot mode
Date: Wed, 9 Nov 2022 17:39:04 -0600 [thread overview]
Message-ID: <20221109233904.scct4fih3b3kvnyk@amd.com> (raw)
In-Reply-To: <20221109205353.984745-2-ltykernel@gmail.com>
On Wed, Nov 09, 2022 at 03:53:36PM -0500, Tianyu Lan wrote:
> From: Tianyu Lan <tiala@microsoft.com>
>
> Hypervisor may pass cc blob address directly into boot param's cc
> blob address in the direct boot mode. Check cc blcb hdr magic first
> in the sev_enable() and use it as cc blob address if check successfully.
>
> Signed-off-by: Tianyu Lan <tiala@microsoft.com>
> ---
> arch/x86/boot/compressed/sev.c | 27 ++++++++++++++++++++-------
> 1 file changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c
> index c93930d5ccbd..960968f8bf75 100644
> --- a/arch/x86/boot/compressed/sev.c
> +++ b/arch/x86/boot/compressed/sev.c
> @@ -272,17 +272,24 @@ static void enforce_vmpl0(void)
>
> void sev_enable(struct boot_params *bp)
> {
> + struct cc_blob_sev_info *cc_info;
> unsigned int eax, ebx, ecx, edx;
> struct msr m;
> bool snp;
>
> /*
> - * bp->cc_blob_address should only be set by boot/compressed kernel.
> - * Initialize it to 0 to ensure that uninitialized values from
> - * buggy bootloaders aren't propagated.
> + * bp->cc_blob_address should only be set by boot/compressed
> + * kernel and hypervisor with direct boot mode. Initialize it
> + * to 0 after checking in order to ensure that uninitialized
> + * values from buggy bootloaders aren't propagated.
> */
> - if (bp)
> - bp->cc_blob_address = 0;
> + if (bp) {
> + cc_info = (struct cc_blob_sev_info *)(unsigned long)
> + bp->cc_blob_address;
> +
> + if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC)
> + bp->cc_blob_address = 0;
It doesn't seem great to rely on SEV_HDR_MAGIC to determine whether
bp->cc_blob_address is valid or not since it is only a 32-bit value.
Would it be possible to use a setup_data entry of type SETUP_CC_BLOB
in bp->hdr.setup_data instead? There's already handling for that in
find_cc_blob_setup_data() so it should "just work".
-Mike
next prev parent reply other threads:[~2022-11-09 23:41 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-09 20:53 [RFC PATCH 00/17] x86/hyperv/sev: Add AMD sev-snp enlightened guest support on hyperv Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 01/17] x86/boot: Check boot param's cc_blob_address for direct boot mode Tianyu Lan
2022-11-09 23:39 ` Michael Roth [this message]
2022-11-10 15:01 ` Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 02/17] x86/sev: Pvalidate memory gab for decompressing kernel Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 03/17] x86/hyperv: Add sev-snp enlightened guest specific config Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 04/17] x86/hyperv: apic change for sev-snp enlightened guest Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 05/17] x86/hyperv: Decrypt hv vp assist page in " Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 06/17] x86/hyperv: Get Virtual Trust Level via hvcall Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 07/17] x86/hyperv: Use vmmcall to implement hvcall in sev-snp enlightened guest Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 08/17] clocksource: hyper-v: decrypt hyperv tsc page " Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 09/17] x86/hyperv: decrypt vmbus pages for " Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 10/17] x86/hyperv: set target vtl in the vmbus init message Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 11/17] drivers: hv: Decrypt percpu hvcall input arg page in sev-snp enlightened guest Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 12/17] Drivers: hv: vmbus: Decrypt vmbus ring buffer Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 13/17] x86/hyperv: Initialize cpu and memory for sev-snp enlightened guest Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 14/17] x86/hyperv: Add smp support for sev-snp guest Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 15/17] x86/hyperv: Add hyperv-specific hadling for VMMCALL under SEV-ES Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 16/17] x86/sev: Add a #HV exception handler Tianyu Lan
2022-11-10 20:38 ` Kalra, Ashish
2022-11-14 1:28 ` Tianyu Lan
2022-11-09 20:53 ` [RFC PATCH 17/17] x86/sev: Initialize #HV doorbell and handle interrupt requests Tianyu Lan
2022-11-10 21:36 ` Kalra, Ashish
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