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Mon, 08 Feb 2021 05:57:19 -0800 (PST) MIME-Version: 1.0 References: <20210203190010.759771-1-richard.henderson@linaro.org> <20210203190010.759771-20-richard.henderson@linaro.org> In-Reply-To: <20210203190010.759771-20-richard.henderson@linaro.org> From: Peter Maydell Date: Mon, 8 Feb 2021 13:57:08 +0000 Message-ID: Subject: Re: [PATCH v5 19/31] linux-user: Handle tags in lock_user/unlock_user To: Richard Henderson Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2a00:1450:4864:20::636; envelope-from=peter.maydell@linaro.org; helo=mail-ej1-x636.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-arm , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 3 Feb 2021 at 19:00, Richard Henderson wrote: > > Resolve the untagged address once, using thread_cpu. > Tidy the DEBUG_REMAP code using glib routines. > > Signed-off-by: Richard Henderson > --- > linux-user/uaccess.c | 29 +++++++++++++++-------------- > 1 file changed, 15 insertions(+), 14 deletions(-) > > diff --git a/linux-user/uaccess.c b/linux-user/uaccess.c > index 30d01f8b30..c696913016 100644 > --- a/linux-user/uaccess.c > +++ b/linux-user/uaccess.c > @@ -6,36 +6,37 @@ > > void *lock_user(int type, abi_ulong guest_addr, size_t len, bool copy) > { > + void *host_addr; > + > + guest_addr = cpu_untagged_addr(thread_cpu, guest_addr); > if (!access_ok_untagged(type, guest_addr, len)) { > return NULL; > } > + host_addr = g2h_untagged(guest_addr); > #ifdef DEBUG_REMAP > - { > - void *addr; > - addr = g_malloc(len); > - if (copy) { > - memcpy(addr, g2h(guest_addr), len); > - } else { > - memset(addr, 0, len); > - } > - return addr; > + if (copy) { > + host_addr = g_memdup(host_addr, len); > + } else { > + host_addr = g_malloc0(len); > } > -#else > - return g2h_untagged(guest_addr); > #endif > + return host_addr; > } > > #ifdef DEBUG_REMAP > void unlock_user(void *host_ptr, abi_ulong guest_addr, size_t len); > { > + void *host_ptr_conv; > + > if (!host_ptr) { > return; > } > - if (host_ptr == g2h_untagged(guest_addr)) { > + host_ptr_conv = g2h(thread_cpu, guest_addr); > + if (host_ptr == host_ptr_conv) { > return; > } > - if (len > 0) { > - memcpy(g2h_untagged(guest_addr), host_ptr, len); > + if (len != 0) { > + memcpy(host_ptr_conv, host_ptr, len); > } Why the change from checking >0 to checking !=0 ? I'd rather not have to go through and audit all the callsites to confirm none of them pass a "length-or-negative-errno" value here... thanks -- PMM