From: Paolo Bonzini <pbonzini@redhat.com>
To: "Stephen Rothwell" <sfr@canb.auug.org.au>,
"Radim Krčmář" <rkrcmar@redhat.com>, KVM <kvm@vger.kernel.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
"Peter Zijlstra" <peterz@infradead.org>
Cc: Linux-Next Mailing List <linux-next@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Tom Lendacky <thomas.lendacky@amd.com>,
Yu Zhang <yu.c.zhang@linux.intel.com>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: Re: linux-next: manual merge of the kvm tree with the tip tree
Date: Fri, 25 Aug 2017 08:39:22 +0200 [thread overview]
Message-ID: <2984689e-ab4e-0c22-7151-adfeeffce4ed@redhat.com> (raw)
In-Reply-To: <20170825143930.494744fe@canb.auug.org.au>
On 25/08/2017 06:39, Stephen Rothwell wrote:
> Hi all,
>
> Today's linux-next merge of the kvm tree got a conflict in:
>
> arch/x86/kvm/mmu.h
>
> between commit:
>
> d0ec49d4de90 ("kvm/x86/svm: Support Secure Memory Encryption within KVM")
>
> from the tip tree and commit:
>
> d1cd3ce90044 ("KVM: MMU: check guest CR3 reserved bits based on its physical address width.")
>
> from the kvm tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
Thomas L., Ingo,
this is completely wrong:
>
> static inline u64 rsvd_bits(int s, int e)
> {
> - return ((1ULL << (e - s + 1)) - 1) << s;
> + return __sme_clr(((1ULL << (e - s + 1)) - 1) << s);
> }
>
First, rsvd_bits is just a simple function to return some 1 bits. Applying
a mask based on properties of the host MMU is incorrect.
Second, the masks computed by __reset_rsvds_bits_mask also apply to
guest page tables, where the C bit is reserved since we don't emulate
SME.
Something like this:
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 2dafd36368cc..e0597d703d72 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4142,16 +4142,24 @@ void
reset_shadow_zero_bits_mask(struct kvm_vcpu *vcpu, struct kvm_mmu *context)
{
bool uses_nx = context->nx || context->base_role.smep_andnot_wp;
+ struct rsvd_bits_validate *shadow_zero_check;
+ int i;
/*
* Passing "true" to the last argument is okay; it adds a check
* on bit 8 of the SPTEs which KVM doesn't use anyway.
*/
- __reset_rsvds_bits_mask(vcpu, &context->shadow_zero_check,
+ shadow_zero_check = &context->shadow_zero_check;
+ __reset_rsvds_bits_mask(vcpu, shadow_zero_check,
boot_cpu_data.x86_phys_bits,
context->shadow_root_level, uses_nx,
guest_cpuid_has(vcpu, X86_FEATURE_GBPAGES),
is_pse(vcpu), true);
+
+ for (i = context->shadow_root_level; --i >= 0; ) {
+ shadow_zero_check->rsvd_bits_mask[i][0] &= ~shadow_me_mask;
+ shadow_zero_check->rsvd_bits_mask[i][1] &= ~shadow_me_mask;
+ }
}
EXPORT_SYMBOL_GPL(reset_shadow_zero_bits_mask);
Can you please fix it up? Please Cc me at paolo.bonzini@gmail.com too
because I'll be on vacation next week.
(And thanks Stephen for the heads-up!)
Paolo
next prev parent reply other threads:[~2017-08-25 6:39 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-25 4:39 linux-next: manual merge of the kvm tree with the tip tree Stephen Rothwell
2017-08-25 6:39 ` Paolo Bonzini [this message]
2017-08-25 13:57 ` Tom Lendacky
2017-08-25 16:53 ` Brijesh Singh
2017-08-25 20:05 ` Paolo Bonzini
2017-08-25 20:41 ` Brijesh Singh
2017-08-25 20:42 ` Paolo Bonzini
2017-08-26 7:24 ` Ingo Molnar
-- strict thread matches above, loose matches on Subject: below --
2023-01-18 0:32 Stephen Rothwell
2022-12-01 0:18 Stephen Rothwell
2022-12-01 0:14 Stephen Rothwell
2022-12-15 23:26 ` Stephen Rothwell
2022-01-10 2:16 Stephen Rothwell
2022-01-10 2:28 ` Like Xu
2021-12-13 17:46 broonie
2021-12-13 18:14 ` Paolo Bonzini
2021-12-13 18:23 ` Mark Brown
2021-10-25 5:11 Stephen Rothwell
2021-10-21 2:39 Stephen Rothwell
2021-10-21 15:32 ` Borislav Petkov
2021-04-22 4:30 Stephen Rothwell
2021-04-22 4:45 ` Nadav Amit
2021-04-22 4:58 ` Stephen Rothwell
2021-04-22 6:29 ` Paolo Bonzini
2020-07-29 6:47 Stephen Rothwell
2020-07-17 5:25 Stephen Rothwell
2020-06-02 4:53 Stephen Rothwell
2020-06-04 3:09 ` Stephen Rothwell
2020-01-16 2:48 Stephen Rothwell
2018-12-19 4:12 Stephen Rothwell
2018-12-17 5:22 Stephen Rothwell
2018-10-19 3:25 Stephen Rothwell
2018-08-08 3:54 Stephen Rothwell
2018-08-15 4:27 ` Stephen Rothwell
2018-08-06 5:12 Stephen Rothwell
2018-08-06 6:27 ` Tianyu Lan
2018-02-02 0:51 Stephen Rothwell
2018-01-15 2:39 Stephen Rothwell
2017-08-28 4:52 Stephen Rothwell
2017-09-04 6:09 ` Stephen Rothwell
2016-11-28 3:56 Stephen Rothwell
2016-11-17 3:50 Stephen Rothwell
2016-11-17 7:07 ` Thomas Gleixner
2016-11-17 21:31 ` Stephen Rothwell
2016-05-12 2:54 Stephen Rothwell
2015-06-19 4:59 Michael Ellerman
2015-05-26 4:45 Stephen Rothwell
2012-11-30 4:26 Stephen Rothwell
2012-05-16 7:14 Stephen Rothwell
2012-05-16 7:53 ` Gleb Natapov
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