linux-kernel - Re: [PATCH] x86/hyper-v: Filter non-canonical addresses passed via HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST(

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] [day] [month] [year] [list]

Message-ID: <175088956523.720749.10160134537876951534.b4-ty@google.com>
Date: Wed, 25 Jun 2025 15:25:29 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Sean Christopherson <seanjc@...gle.com>, kvm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Manuel Andreas <manuel.andreas@....de>
Cc: Vitaly Kuznetsov <vkuznets@...hat.com>, pbonzini@...hat.com
Subject: Re: [PATCH] x86/hyper-v: Filter non-canonical addresses passed via HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST(_EX)

On Wed, 25 Jun 2025 15:53:19 +0200, Manuel Andreas wrote:
> In KVM guests with Hyper-V hypercalls enabled, the hypercalls
> HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST and HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX
> allow a guest to request invalidation of portions of a virtual TLB.
> For this, the hypercall parameter includes a list of GVAs that are supposed
> to be invalidated.
> 
> However, when non-canonical GVAs are passed, there is currently no
> filtering in place and they are eventually passed to checked invocations of
> INVVPID on Intel / INVLPGA on AMD.
> While the AMD variant (INVLPGA) will silently ignore the non-canonical
> address and perform a no-op, the Intel variant (INVVPID) will fail and end
> up in invvpid_error, where a WARN_ONCE is triggered:
> 
> [...]

Applied to kvm-x86 fixes, with a massaged changelog, e.g. to call out that
"real" Hyper-V behaves this way.  Thanks!

[1/1] x86/hyper-v: Filter non-canonical addresses passed via HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST(_EX)
      https://github.com/kvm-x86/linux/commit/fa787ac07b3c

--
https://github.com/kvm-x86/kvm-unit-tests/tree/next