linux-kernel - Re: [RFC PATCH V3 01/11] x86/HV: Initialize GHCB page in Isolation VM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 9 Jun 2021 14:38:29 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Tianyu Lan <ltykernel@...il.com>
Cc:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
        wei.liu@...nel.org, decui@...rosoft.com, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, x86@...nel.org, hpa@...or.com,
        arnd@...db.de, dave.hansen@...ux.intel.com, luto@...nel.org,
        peterz@...radead.org, akpm@...ux-foundation.org,
        kirill.shutemov@...ux.intel.com, rppt@...nel.org,
        hannes@...xchg.org, cai@....pw, krish.sadhukhan@...cle.com,
        saravanand@...com, Tianyu.Lan@...rosoft.com,
        konrad.wilk@...cle.com, hch@....de, m.szyprowski@...sung.com,
        robin.murphy@....com, boris.ostrovsky@...cle.com, jgross@...e.com,
        sstabellini@...nel.org, will@...nel.org,
        xen-devel@...ts.xenproject.org, davem@...emloft.net,
        kuba@...nel.org, jejb@...ux.ibm.com, martin.petersen@...cle.com,
        iommu@...ts.linux-foundation.org, linux-arch@...r.kernel.org,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-scsi@...r.kernel.org, netdev@...r.kernel.org,
        vkuznets@...hat.com, thomas.lendacky@....com,
        brijesh.singh@....com, sunilmut@...rosoft.com
Subject: Re: [RFC PATCH V3 01/11] x86/HV: Initialize GHCB page in Isolation VM

On Sun, May 30, 2021 at 11:06:18AM -0400, Tianyu Lan wrote:
> From: Tianyu Lan <Tianyu.Lan@...rosoft.com>
> 
> Hyper-V exposes GHCB page via SEV ES GHCB MSR for SNP guest
> to communicate with hypervisor. Map GHCB page for all
> cpus to read/write MSR register and submit hvcall request
> via GHCB.
> 
> Signed-off-by: Tianyu Lan <Tianyu.Lan@...rosoft.com>
> ---
>  arch/x86/hyperv/hv_init.c       | 60 ++++++++++++++++++++++++++++++---
>  arch/x86/include/asm/mshyperv.h |  2 ++
>  include/asm-generic/mshyperv.h  |  2 ++
>  3 files changed, 60 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index bb0ae4b5c00f..dc74d01cb859 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -60,6 +60,9 @@ static int hv_cpu_init(unsigned int cpu)
>  	struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
>  	void **input_arg;
>  	struct page *pg;
> +	u64 ghcb_gpa;
> +	void *ghcb_va;
> +	void **ghcb_base;

Any reason you can't reuse the SEV-ES support code in the Linux kernel?
It already has code to setup GHCBs for all vCPUs.

I see that you don't need #VC handling in your SNP VMs because of the
paravisor running underneath it, but just re-using the GHCB setup code
shouldn't be too hard.

Regards,

	Joerg