From: "Huang, Kai" <kai.huang@intel.com>
To: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"Hansen, Dave" <dave.hansen@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "Luck, Tony" <tony.luck@intel.com>,
"bagasdotme@gmail.com" <bagasdotme@gmail.com>,
"ak@linux.intel.com" <ak@linux.intel.com>,
"Wysocki, Rafael J" <rafael.j.wysocki@intel.com>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>, "Christopherson,,
Sean" <seanjc@google.com>,
"Chatre, Reinette" <reinette.chatre@intel.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"Yamahata, Isaku" <isaku.yamahata@intel.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"Shahar, Sagi" <sagis@google.com>,
"imammedo@redhat.com" <imammedo@redhat.com>,
"Gao, Chao" <chao.gao@intel.com>,
"Brown, Len" <len.brown@intel.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"sathyanarayanan.kuppuswamy@linux.intel.com"
<sathyanarayanan.kuppuswamy@linux.intel.com>,
"Huang, Ying" <ying.huang@intel.com>,
"Williams, Dan J" <dan.j.williams@intel.com>
Subject: Re: [PATCH v8 11/16] x86/virt/tdx: Designate reserved areas for all TDMRs
Date: Wed, 11 Jan 2023 22:10:56 +0000 [thread overview]
Message-ID: <7dba73c8900a47890452b53509d7088779415265.camel@intel.com> (raw)
In-Reply-To: <0293d72e-e03f-03d7-5982-29b4f11006a9@intel.com>
On Wed, 2023-01-11 at 08:16 -0800, Dave Hansen wrote:
> On 1/11/23 02:57, Huang, Kai wrote:
> > On Tue, 2023-01-10 at 07:19 -0800, Dave Hansen wrote:
> > > On 1/10/23 03:01, Huang, Kai wrote:
> > > > On Mon, 2023-01-09 at 17:22 -0800, Dave Hansen wrote:
> > > > > On 1/9/23 17:19, Huang, Kai wrote:
> > > > > > > It's probably also worth noting *somewhere* that there's a balance to be
> > > > > > > had between TDMRs and reserved areas. A system that is running out of
> > > > > > > reserved areas in a TDMR could split a TDMR to get more reserved areas.
> > > > > > > A system that has run out of TDMRs could relatively easily coalesce two
> > > > > > > adjacent TDMRs (before the PAMTs are allocated) and use a reserved area
> > > > > > > if there was a gap between them.
> > > > > > We can add above to the changelog of this patch, or the patch 09 ("x86/virt/tdx:
> > > > > > Fill out TDMRs to cover all TDX memory regions"). The latter perhaps is better
> > > > > > since that patch is the first place where the balance of TDMRs and reserved
> > > > > > areas is related.
> > > > > >
> > > > > > What is your suggestion?
> > > > > Just put it close to the code that actually hits the problem so the
> > > > > potential solution is close at hand to whoever hits the problem.
> > > > >
> > > > Sorry to double check: the code which hits the problem is the 'if (idx >=
> > > > max_reserved_per_tdmr)' check in tdmr_add_rsvd_area(), so I think I can add
> > > > right before this check?
> > >
> > > Please just hack together how you think it should look and either reply
> > > with an updated patch, or paste the relevant code snippet in your reply.
> > > That'll keep me from having to go chase this code back down.
> > >
> >
> > Thanks for the tip. How about below?
> >
> > static int tdmr_add_rsvd_area(struct tdmr_info *tdmr, int *p_idx, u64 addr,
> > u64 size, u16 max_reserved_per_tdmr)
> > {
> > struct tdmr_reserved_area *rsvd_areas = tdmr->reserved_areas;
> > int idx = *p_idx;
> >
> > /* Reserved area must be 4K aligned in offset and size */
> > if (WARN_ON(addr & ~PAGE_MASK || size & ~PAGE_MASK))
> > return -EINVAL;
> >
> > /*
> > * The TDX module supports only limited number of TDMRs and
> > * limited number of reserved areas for each TDMR. There's a
> > * balance to be had between TDMRs a2nd reserved areas. A system
> > * that is running out of reserved areas in a TDMR could split a
> > * TDMR to get more reserved areas. A system that has run out
> > * of TDMRs could relatively easily coalesce two adjacent TDMRs
> > * (before the PAMTs are allocated) and use a reserved area if
> > * there was a gap between them.
> > */
> > if (idx >= max_reserved_per_tdmr) {
> > pr_warn("too many reserved areas for TDMR [0x%llx, 0x%llx)\n",
> > tdmr->base, tdmr_end(tdmr));
> > return -ENOSPC;
> > }
>
> This isn't really converging on a solution. At this point, I just see
> my verbatim text being copied and pasted into these functions without
> really anything additional.
>
> This comment, for instance, just blathers about what could be done but
> doesn't actually explain what it is doing here.
>
> But, again, this isn't converging. It's just thrashing and not getting
> any better. I guess I'll just fix it up best I can when I apply it.
Appreciate your help!
next prev parent reply other threads:[~2023-01-11 22:11 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-09 6:52 [PATCH v8 00/16] TDX host kernel support Kai Huang
2022-12-09 6:52 ` [PATCH v8 01/16] x86/tdx: Define TDX supported page sizes as macros Kai Huang
2023-01-06 19:04 ` Dave Hansen
2022-12-09 6:52 ` [PATCH v8 02/16] x86/virt/tdx: Detect TDX during kernel boot Kai Huang
2023-01-06 17:09 ` Dave Hansen
2023-01-08 22:25 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 03/16] x86/virt/tdx: Make INTEL_TDX_HOST depend on X86_X2APIC Kai Huang
2023-01-06 19:04 ` Dave Hansen
2022-12-09 6:52 ` [PATCH v8 04/16] x86/virt/tdx: Add skeleton to initialize TDX on demand Kai Huang
2023-01-06 17:14 ` Dave Hansen
2023-01-08 22:26 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 05/16] x86/virt/tdx: Implement functions to make SEAMCALL Kai Huang
2023-01-06 17:29 ` Dave Hansen
2023-01-09 10:30 ` Huang, Kai
2023-01-09 19:54 ` Dave Hansen
2023-01-09 22:10 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 06/16] x86/virt/tdx: Get information about TDX module and TDX-capable memory Kai Huang
2023-01-06 17:46 ` Dave Hansen
2023-01-09 10:25 ` Huang, Kai
2023-01-09 19:52 ` Dave Hansen
2023-01-09 22:07 ` Huang, Kai
2023-01-09 22:11 ` Dave Hansen
2022-12-09 6:52 ` [PATCH v8 07/16] x86/virt/tdx: Use all system memory when initializing TDX module as TDX memory Kai Huang
2023-01-06 18:18 ` Dave Hansen
2023-01-09 11:48 ` Huang, Kai
2023-01-09 16:51 ` Dave Hansen
2023-01-10 12:09 ` Huang, Kai
2023-01-10 16:18 ` Dave Hansen
2023-01-11 10:00 ` Huang, Kai
2023-01-12 0:56 ` Huang, Ying
2023-01-12 1:18 ` Huang, Kai
2023-01-12 1:59 ` Huang, Ying
2023-01-12 2:22 ` Huang, Kai
2023-01-12 11:33 ` Huang, Kai
2023-01-18 11:08 ` Huang, Kai
2023-01-18 13:57 ` David Hildenbrand
2023-01-18 19:38 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 08/16] x86/virt/tdx: Add placeholder to construct TDMRs to cover all TDX memory regions Kai Huang
2023-01-06 19:24 ` Dave Hansen
2023-01-10 0:40 ` Huang, Kai
2023-01-10 0:47 ` Dave Hansen
2023-01-10 2:23 ` Huang, Kai
2023-01-10 19:12 ` Dave Hansen
2023-01-11 9:23 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 09/16] x86/virt/tdx: Fill out " Kai Huang
2023-01-06 19:36 ` Dave Hansen
2023-01-10 0:45 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 10/16] x86/virt/tdx: Allocate and set up PAMTs for TDMRs Kai Huang
2023-01-06 21:53 ` Dave Hansen
2023-01-10 0:49 ` Huang, Kai
2023-01-07 0:47 ` Dave Hansen
2023-01-10 0:47 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 11/16] x86/virt/tdx: Designate reserved areas for all TDMRs Kai Huang
2023-01-06 22:07 ` Dave Hansen
2023-01-10 1:19 ` Huang, Kai
2023-01-10 1:22 ` Dave Hansen
2023-01-10 11:01 ` Huang, Kai
2023-01-10 15:19 ` Dave Hansen
2023-01-11 10:57 ` Huang, Kai
2023-01-11 16:16 ` Dave Hansen
2023-01-11 22:10 ` Huang, Kai [this message]
2023-01-10 11:01 ` Huang, Kai
2023-01-10 15:17 ` Dave Hansen
2022-12-09 6:52 ` [PATCH v8 12/16] x86/virt/tdx: Designate the global KeyID and configure the TDX module Kai Huang
2023-01-06 22:21 ` Dave Hansen
2023-01-10 10:48 ` Huang, Kai
2023-01-10 16:25 ` Dave Hansen
2023-01-10 23:33 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 13/16] x86/virt/tdx: Configure global KeyID on all packages Kai Huang
2023-01-06 22:49 ` Dave Hansen
2023-01-10 10:15 ` Huang, Kai
2023-01-10 16:53 ` Dave Hansen
2023-01-11 0:06 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 14/16] x86/virt/tdx: Initialize all TDMRs Kai Huang
2023-01-07 0:17 ` Dave Hansen
2023-01-10 10:23 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 15/16] x86/virt/tdx: Flush cache in kexec() when TDX is enabled Kai Huang
2023-01-07 0:35 ` Dave Hansen
2023-01-10 11:29 ` Huang, Kai
2023-01-10 15:27 ` Dave Hansen
2023-01-11 0:13 ` Huang, Kai
2023-01-11 0:30 ` Dave Hansen
2023-01-11 1:58 ` Huang, Kai
2022-12-09 6:52 ` [PATCH v8 16/16] Documentation/x86: Add documentation for TDX host support Kai Huang
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