From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [RFC PATCH v1 03/28] kvm: svm: Use the hardware provided GPA instead of page walk Date: Wed, 21 Sep 2016 19:16:59 +0200 Message-ID: <20160921171659.cvtkp5nf3r3afawi@pd.tnic> References: <147190820782.9523.4967724730957229273.stgit@brijesh-build-machine> <147190824754.9523.13923968456167130181.stgit@brijesh-build-machine> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: <147190824754.9523.13923968456167130181.stgit@brijesh-build-machine> Sender: owner-linux-mm@kvack.org To: Brijesh Singh Cc: simon.guinot@sequanux.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, rkrcmar@redhat.com, matt@codeblueprint.co.uk, linus.walleij@linaro.org, linux-mm@kvack.org, paul.gortmaker@windriver.com, hpa@zytor.com, dan.j.williams@intel.com, aarcange@redhat.com, sfr@canb.auug.org.au, andriy.shevchenko@linux.intel.com, herbert@gondor.apana.org.au, bhe@redhat.com, xemul@parallels.com, joro@8bytes.org, x86@kernel.org, mingo@redhat.com, msalter@redhat.com, ross.zwisler@linux.intel.com, dyoung@redhat.com, thomas.lendacky@amd.com, jroedel@suse.de, keescook@chromium.org, toshi.kani@hpe.com, mathieu.desnoyers@efficios.com, devel@linuxdriverproject.org, tglx@linutronix.de, mchehab@kernel.org, iamjoonsoo.kim@lge.com, labbott@fedoraproject.org, tony.luck@intel.com, alexandre.bounine@idt.com, kuleshovmail@gmail.com, linux-kernel@vger.kernel.org, mcgrof@kernel.org, linux-crypto@vger.k List-Id: linux-efi@vger.kernel.org On Mon, Aug 22, 2016 at 07:24:07PM -0400, Brijesh Singh wrote: > From: Tom Lendacky > > When a guest causes a NPF which requires emulation, KVM sometimes walks > the guest page tables to translate the GVA to a GPA. This is unnecessary > most of the time on AMD hardware since the hardware provides the GPA in > EXITINFO2. > > The only exception cases involve string operations involving rep or > operations that use two memory locations. With rep, the GPA will only be > the value of the initial NPF and with dual memory locations we won't know > which memory address was translated into EXITINFO2. > > Signed-off-by: Tom Lendacky > --- > arch/x86/include/asm/kvm_emulate.h | 3 +++ > arch/x86/include/asm/kvm_host.h | 3 +++ > arch/x86/kvm/svm.c | 2 ++ > arch/x86/kvm/x86.c | 17 ++++++++++++++++- > 4 files changed, 24 insertions(+), 1 deletion(-) FWIW, LGTM. (Gotta love replying in acronyms :-)) Reviewed-by: Borislav Petkov -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) -- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org