From: Marc Orr <marcorr@google.com>
To: sean.j.christopherson@intel.com
Cc: dave.hansen@intel.com, kvm@vger.kernel.org,
Jim Mattson <jmattson@google.com>,
David Rientjes <rientjes@google.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
linux-mm@kvack.org, akpm@linux-foundation.org,
pbonzini@redhat.com, rkrcmar@redhat.com, willy@infradead.org,
dave.hansen@linux.intel.com, Wanpeng Li <kernellwp@gmail.com>
Subject: Re: [kvm PATCH v5 3/4] kvm: vmx: refactor vmx_msrs struct for vmalloc
Date: Wed, 31 Oct 2018 14:19:08 +0000 [thread overview]
Message-ID: <CAA03e5GzBSg_ZkfX0DGd4a1tPAoP_71Q-L3px62htB0-vzqhAQ@mail.gmail.com> (raw)
In-Reply-To: <20181031141547.GA13907@linux.intel.com>
On Wed, Oct 31, 2018 at 7:15 AM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> On Wed, Oct 31, 2018 at 07:12:16AM -0700, Dave Hansen wrote:
> > On 10/31/18 6:26 AM, Marc Orr wrote:
> > > +/*
> > > + * To prevent vmx_msr_entry array from crossing a page boundary, require:
> > > + * sizeof(*vmx_msrs.vmx_msr_entry.val) to be a power of two. This is guaranteed
> > > + * through compile-time asserts that:
> > > + * - NR_AUTOLOAD_MSRS * sizeof(struct vmx_msr_entry) is a power of two
> > > + * - NR_AUTOLOAD_MSRS * sizeof(struct vmx_msr_entry) <= PAGE_SIZE
> > > + * - The allocation of vmx_msrs.vmx_msr_entry.val is aligned to its size.
> > > + */
> >
> > Why do we need to prevent them from crossing a page boundary?
>
> The VMCS takes the physical address of the load/store lists. I
> requested that this information be added to the changelog. Marc
> deferred addressing my comments since there's a decent chance
> patches 3/4 and 4/4 will be dropped in the end.
Exactly. And the code (in these patches) to map these virtual address
to physical addresses operates at page granularity, and will break for
memory that spans a single page.
next prev parent reply other threads:[~2018-10-31 14:19 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-31 13:26 [kvm PATCH v5 0/4] shrink vcpu_vmx down to order 2 Marc Orr
2018-10-31 13:26 ` [kvm PATCH v5 1/4] kvm: x86: Use task structs fpu field for user Marc Orr
2018-10-31 13:26 ` [kvm PATCH v5 2/4] kvm: x86: Dynamically allocate guest_fpu Marc Orr
2018-10-31 14:11 ` Dave Hansen
2018-10-31 21:13 ` Marc Orr
2018-10-31 21:21 ` Dave Hansen
2018-10-31 21:24 ` Marc Orr
2018-10-31 21:30 ` Dave Hansen
2018-10-31 21:39 ` Marc Orr
2018-10-31 21:44 ` Dave Hansen
2018-10-31 13:26 ` [kvm PATCH v5 3/4] kvm: vmx: refactor vmx_msrs struct for vmalloc Marc Orr
2018-10-31 14:12 ` Dave Hansen
2018-10-31 14:15 ` Sean Christopherson
2018-10-31 14:19 ` Marc Orr [this message]
2018-10-31 13:26 ` [kvm PATCH v5 4/4] kvm: vmx: use vmalloc() to allocate vcpus Marc Orr
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