KVM Archive on lore.kernel.org
 help / color / Atom feed
From: Yang Weijiang <weijiang.yang@intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Yang Weijiang <weijiang.yang@intel.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	pbonzini@redhat.com, jmattson@google.com,
	yu.c.zhang@linux.intel.com, alazar@bitdefender.com,
	edwin.zhai@intel.com
Subject: Re: [RESEND PATCH v10 04/10] mmu: spp: Add functions to operate SPP access bitmap
Date: Mon, 13 Jan 2020 14:15:06 +0800
Message-ID: <20200113061506.GD12253@local-michael-cet-test.sh.intel.com> (raw)
In-Reply-To: <20200110173804.GD21485@linux.intel.com>

On Fri, Jan 10, 2020 at 09:38:04AM -0800, Sean Christopherson wrote:
> On Thu, Jan 02, 2020 at 02:13:13PM +0800, Yang Weijiang wrote:
> > Create access bitmap for SPP subpages, the bitmap can
> > be accessed with a gfn. The initial access bitmap for each
> > physical page is 0xFFFFFFFF, meaning SPP is not enabled for the
> > subpages.
> 
> Wrap changelogs at ~75 chars.
> 
> Create access bitmap for SPP subpages, the bitmap can be accessed with a
> gfn.  The initial access bitmap for each physical page is 0xFFFFFFFF,
> meaning SPP is not enabled for the subpages.
> 
> There needs to be a *lot* more information provided in all of the changelogs
> for this series.  I understand the basic concepts of SPP, but nothing in the
> documentation or changelogs explains how KVM generates the SPP tables based
> on userspace input.  Essentially, explain the design in decent detail, with
> a focus on *why* KVM does what it does.
>
OK, will modify the documentation to add SPPT setup section, thanks!

> > +static int kvm_spp_level_pages(gfn_t gfn_lower, gfn_t gfn_upper, int level)
> > +{
> > +	int page_num = KVM_PAGES_PER_HPAGE(level);
> > +	gfn_t gfn_max = (gfn_lower & ~(page_num - 1)) + page_num - 1;
> > +	int ret;
> > +
> > +	if (gfn_upper <= gfn_max)
> > +		ret = gfn_upper - gfn_lower + 1;
> > +	else
> > +		ret = gfn_max - gfn_lower + 1;
> > +
> > +	return ret;
> > +}
> > +
> >  #define SPPT_ENTRY_PHA_MASK (0xFFFFFFFFFF << 12)
> 
> There's almost certainly an existing macro for this.
>
Sure, will remove it.
> >  
> >  int kvm_spp_setup_structure(struct kvm_vcpu *vcpu,
> > @@ -220,6 +249,309 @@ int kvm_spp_setup_structure(struct kvm_vcpu *vcpu,
> >  }
> >  EXPORT_SYMBOL_GPL(kvm_spp_setup_structure);
> >  
> > +int vmx_spp_flush_sppt(struct kvm *kvm, u64 gfn_base, u32 npages)
> > +{
> > +	struct kvm_shadow_walk_iterator iter;
> > +	struct kvm_vcpu *vcpu;
> > +	gfn_t gfn = gfn_base;
> > +	gfn_t gfn_max = gfn_base + npages - 1;
> 
> s/gfn_max/gfn_end.  "max" makes me think this is literally walking every
> possible gfn.
> 
Make sense, will change it.

> > +	u64 spde;
> > +	int count;
> > +	bool flush = false;
> > +
> >  /*
> >   * The bit 0 ~ bit 15 of kvm_memory_region::flags are visible for userspace,
> >   * other bits are reserved for kvm internal use which are defined in
> > -- 
> > 2.17.2
> > 

  reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-02  6:13 [RESEND PATCH v10 00/10] Enable Sub-Page Write Protection Support Yang Weijiang
2020-01-02  6:13 ` [RESEND PATCH v10 01/10] Documentation: Add EPT based Subpage Protection and related APIs Yang Weijiang
2020-01-02  6:13 ` [RESEND PATCH v10 02/10] vmx: spp: Add control flags for Sub-Page Protection(SPP) Yang Weijiang
2020-01-10 16:58   ` Sean Christopherson
2020-01-13  5:44     ` Yang Weijiang
2020-01-02  6:13 ` [RESEND PATCH v10 03/10] mmu: spp: Add SPP Table setup functions Yang Weijiang
2020-01-10 17:26   ` Sean Christopherson
2020-01-13  6:00     ` Yang Weijiang
2020-01-10 17:40   ` Sean Christopherson
2020-01-13  6:04     ` Yang Weijiang
2020-01-02  6:13 ` [RESEND PATCH v10 04/10] mmu: spp: Add functions to operate SPP access bitmap Yang Weijiang
2020-01-10 17:38   ` Sean Christopherson
2020-01-13  6:15     ` Yang Weijiang [this message]
2020-01-02  6:13 ` [RESEND PATCH v10 05/10] x86: spp: Introduce user-space SPP IOCTLs Yang Weijiang
2020-01-10 18:10   ` Sean Christopherson
2020-01-13  8:21     ` Yang Weijiang
2020-01-02  6:13 ` [RESEND PATCH v10 06/10] vmx: spp: Set up SPP paging table at vmentry/vmexit Yang Weijiang
2020-01-10 17:55   ` Sean Christopherson
2020-01-13  6:50     ` Yang Weijiang
2020-01-21 14:01     ` Paolo Bonzini
2020-01-10 18:04   ` Sean Christopherson
2020-01-13  8:10     ` Yang Weijiang
2020-01-13 17:33       ` Sean Christopherson
2020-01-13 18:55         ` Adalbert Lazăr
2020-01-13 21:47           ` Sean Christopherson
2020-01-14  3:08         ` Yang Weijiang
2020-01-14 18:58           ` Sean Christopherson
2020-01-15  1:36             ` Yang Weijiang
2020-01-21 14:14             ` Paolo Bonzini
2020-01-02  6:13 ` [RESEND PATCH v10 07/10] mmu: spp: Enable Lazy mode SPP protection Yang Weijiang
2020-01-02  6:13 ` [RESEND PATCH v10 08/10] mmu: spp: Handle SPP protected pages when VM memory changes Yang Weijiang
2020-01-02  6:13 ` [RESEND PATCH v10 09/10] x86: spp: Add SPP protection check in emulation Yang Weijiang
2020-01-02  6:13 ` [RESEND PATCH v10 10/10] kvm: selftests: selftest for Sub-Page protection Yang Weijiang
  -- strict thread matches above, loose matches on Subject: below --
2020-01-02  5:18 [RESEND PATCH v10 00/10] Enable Sub-Page Write Protection Support Yang Weijiang
2020-01-02  5:18 ` [RESEND PATCH v10 04/10] mmu: spp: Add functions to operate SPP access bitmap Yang Weijiang

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200113061506.GD12253@local-michael-cet-test.sh.intel.com \
    --to=weijiang.yang@intel.com \
    --cc=alazar@bitdefender.com \
    --cc=edwin.zhai@intel.com \
    --cc=jmattson@google.com \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=sean.j.christopherson@intel.com \
    --cc=yu.c.zhang@linux.intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

KVM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/kvm/0 kvm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 kvm kvm/ https://lore.kernel.org/kvm \
		kvm@vger.kernel.org
	public-inbox-index kvm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.kvm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git