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[34.168.104.7]) by smtp.gmail.com with ESMTPSA id z12-20020a1709027e8c00b0016dbaf3ff2esm48576pla.22.2022.10.06.13.23.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Oct 2022 13:23:56 -0700 (PDT) Date: Thu, 6 Oct 2022 20:23:52 +0000 From: Sean Christopherson To: Vishal Annapurve Cc: x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, pbonzini@redhat.com, vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, shuah@kernel.org, yang.zhong@intel.com, drjones@redhat.com, ricarkol@google.com, aaronlewis@google.com, wei.w.wang@intel.com, kirill.shutemov@linux.intel.com, corbet@lwn.net, hughd@google.com, jlayton@kernel.org, bfields@fieldses.org, akpm@linux-foundation.org, chao.p.peng@linux.intel.com, yu.c.zhang@linux.intel.com, jun.nakajima@intel.com, dave.hansen@intel.com, michael.roth@amd.com, qperret@google.com, steven.price@arm.com, ak@linux.intel.com, david@redhat.com, luto@kernel.org, vbabka@suse.cz, marcorr@google.com, erdemaktas@google.com, pgonda@google.com, nikunj@amd.com, diviness@google.com, maz@kernel.org, dmatlack@google.com, axelrasmussen@google.com, maciej.szmigiero@oracle.com, mizhang@google.com, bgardon@google.com Subject: Re: [RFC V3 PATCH 6/6] sefltests: kvm: x86: Add selftest for private memory Message-ID: References: <20220819174659.2427983-1-vannapurve@google.com> <20220819174659.2427983-7-vannapurve@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220819174659.2427983-7-vannapurve@google.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, Aug 19, 2022, Vishal Annapurve wrote: > +static bool verify_mem_contents(void *mem, uint32_t size, uint8_t pat) As per feedback in v1[*], spell out "pattern". [*] https://lore.kernel.org/all/YtiJx11AZHslcGnN@google.com > +{ > + uint8_t *buf = (uint8_t *)mem; > + > + for (uint32_t i = 0; i < size; i++) { > + if (buf[i] != pat) > + return false; > + } > + > + return true; > +} > + > +/* > + * Add custom implementation for memset to avoid using standard/builtin memset > + * which may use features like SSE/GOT that don't work with guest vm execution > + * within selftests. > + */ > +void *memset(void *mem, int byte, size_t size) > +{ > + uint8_t *buf = (uint8_t *)mem; > + > + for (uint32_t i = 0; i < size; i++) > + buf[i] = byte; > + > + return buf; > +} memset(), memcpy(), and memcmp() are safe to use as of commit 6b6f71484bf4 ("KVM: selftests: Implement memcmp(), memcpy(), and memset() for guest use"). Note the "fun" with gcc "optimizing" into infinite recursion... :-) > + > +static void populate_test_area(void *test_area_base, uint64_t pat) > +{ > + memset(test_area_base, pat, TEST_AREA_SIZE); > +} > + > +static void populate_guest_test_mem(void *guest_test_mem, uint64_t pat) > +{ > + memset(guest_test_mem, pat, GUEST_TEST_MEM_SIZE); > +} > + > +static bool verify_test_area(void *test_area_base, uint64_t area_pat, > + uint64_t guest_pat) Again, avoid "pat". > +{ > + void *test_area1_base = test_area_base; > + uint64_t test_area1_size = GUEST_TEST_MEM_OFFSET; > + void *guest_test_mem = test_area_base + test_area1_size; > + uint64_t guest_test_size = GUEST_TEST_MEM_SIZE; > + void *test_area2_base = guest_test_mem + guest_test_size; > + uint64_t test_area2_size = (TEST_AREA_SIZE - (GUEST_TEST_MEM_OFFSET + > + GUEST_TEST_MEM_SIZE)); This is all amazingly hard to read. AFAICT, the local variables are largely useless. Actually, why even take in @test_area_base, isn't it hardcoded to TEST_AREA_GPA? Then everything except the pattern can be hardcoded. > + return (verify_mem_contents(test_area1_base, test_area1_size, area_pat) && > + verify_mem_contents(guest_test_mem, guest_test_size, guest_pat) && > + verify_mem_contents(test_area2_base, test_area2_size, area_pat)); > +}