From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB9432236E8; Tue, 22 Jul 2025 15:47:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753199249; cv=none; b=GhdNUl6EoCT7oqH5t8+v6KB1BZHfU8jlUyiEqdKqSJntJFng1fVF0oOvF2+JXNlwn/TKTkWkaI7waNbhbqi1vE7yw5H64jGm9+nKCuCtQvQM3nE4DJ/qsoTLwT/O4A/xNWHBqzF8i3DCpVmHelnLf+jZuSpeZ5+JLSQUxdxA3do= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753199249; c=relaxed/simple; bh=M3Mc51dw7b8Gz9b/pdMV6wSzhw/d2UXhK7/Q+XXRt9c=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=l9IzjQRXImSQCGmUqIqgSFPU/RsuyZAOZbeW4UuSrsw7XIhkgGsD5EcyxkUUz+RYaQpgiJrxwEhPjC2pzORjcIHORJia8q0dXyQPzJ7HjX3Pv343bKARcjQ8xmht9GTFeMSFja7MP6chkebxqzyHCAkHWQvoGgZ//47zO/bfIVM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=U3eI/avi; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="U3eI/avi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BBC1C4CEEB; Tue, 22 Jul 2025 15:47:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753199249; bh=M3Mc51dw7b8Gz9b/pdMV6wSzhw/d2UXhK7/Q+XXRt9c=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=U3eI/aviIJXp8gXKT1xbu+rMiWmUs7riUKvyqXgOQ+FepLvXOfJPUAtaeByyVeygF kxYHkSq9sEubs3CmSIQ4L8sUo08d7jLBwKQX9gM1C0hjs8oTyb/dLu3WVQK25AUNWe /DbCBI3o6o1qcXSKoeSr1MapTL4L5ANg8tC2x8e37JEqPwJRCwQV+0QN0KXwwQpbDK UijxJh72OZFEhsu4YCP4o4gtBhTpRD6LRXe0XvB9XOdvzqFB8XDbJpFk1xCxGoy+bA oPEkQxjUulFPw2ZrCzLBiJTbNUOlZLVpqMsBOzRpLd0VSxTzQNLx9c2fTGZ7Sil44k 8TjrJJCjgHx8Q== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1ueFDD-000P2e-0K; Tue, 22 Jul 2025 16:47:27 +0100 Date: Tue, 22 Jul 2025 16:47:26 +0100 Message-ID: <86h5z48bxt.wl-maz@kernel.org> From: Marc Zyngier To: Andrew Jones Cc: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Suzuki K Poulose , Oliver Upton , Zenghui Yu , Will Deacon , Mark Rutland , jackabt@amazon.com Subject: Re: [PATCH] KVM: arm64: selftest: Add standalone test checking for KVM's own UUID In-Reply-To: <20250722-87ac9d7e0b27cf7c67a4fbd3@orel> References: <20250721155136.892255-1-maz@kernel.org> <20250722-87ac9d7e0b27cf7c67a4fbd3@orel> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: ajones@ventanamicro.com, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com, will@kernel.org, mark.rutland@arm.com, jackabt@amazon.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Tue, 22 Jul 2025 10:18:10 +0100, Andrew Jones wrote: > > Hi Marc, > > On Mon, Jul 21, 2025 at 04:51:36PM +0100, Marc Zyngier wrote: > > Tinkering with UUIDs is a perilious task, and the KVM UUID gets > > broken at times. In order to spot this early enough, add a selftest > > that will shout if the expected value isn't found. > > > > Signed-off-by: Marc Zyngier > > Link: https://lore.kernel.org/r/20250721130558.50823-1-jackabt.amazon@gmail.com > > --- > > tools/testing/selftests/kvm/Makefile.kvm | 1 + > > tools/testing/selftests/kvm/arm64/kvm-uuid.c | 67 ++++++++++++++++++++ > > 2 files changed, 68 insertions(+) > > create mode 100644 tools/testing/selftests/kvm/arm64/kvm-uuid.c > > > > diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm > > index ce817a975e50a..e1eb1ba238a2a 100644 > > --- a/tools/testing/selftests/kvm/Makefile.kvm > > +++ b/tools/testing/selftests/kvm/Makefile.kvm > > @@ -167,6 +167,7 @@ TEST_GEN_PROGS_arm64 += arm64/vgic_irq > > TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress > > TEST_GEN_PROGS_arm64 += arm64/vpmu_counter_access > > TEST_GEN_PROGS_arm64 += arm64/no-vgic-v3 > > +TEST_GEN_PROGS_arm64 += arm64/kvm-uuid > > TEST_GEN_PROGS_arm64 += access_tracking_perf_test > > TEST_GEN_PROGS_arm64 += arch_timer > > TEST_GEN_PROGS_arm64 += coalesced_io_test > > diff --git a/tools/testing/selftests/kvm/arm64/kvm-uuid.c b/tools/testing/selftests/kvm/arm64/kvm-uuid.c > > new file mode 100644 > > index 0000000000000..89d9c8b182ae5 > > --- /dev/null > > +++ b/tools/testing/selftests/kvm/arm64/kvm-uuid.c > > @@ -0,0 +1,67 @@ > > +#include > > +#include > > +#include > > +#include > > + > > +#include "processor.h" > > + > > +/* > > + * Do NOT redefine these constants, or try to replace them with some > > + * "common" version. They are hardcoded here to detect any potential > > + * breakage happening in the rest of the kernel. > > + * > > + * KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 > > + */ > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 0xb66fb428U > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 0xe911c52eU > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 0x564bcaa9U > > +#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3 0x743a004dU > > + > > +static void guest_code(void) > > +{ > > + struct arm_smccc_res res = {}; > > + > > + smccc_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, 0, 0, 0, 0, 0, 0, 0, &res); > > + > > + __GUEST_ASSERT(res.a0 != SMCCC_RET_NOT_SUPPORTED, "a0 = %lx\n", res.a0); > > Should this check res.a0 == SMCCC_RET_SUCCESS instead? Yeah, probably. > > > + __GUEST_ASSERT(res.a0 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 && > > + res.a1 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 && > > + res.a2 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 && > > + res.a3 == ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3, > > + "Unexpected KVM-specific UID %lx %lx %lx %lx\n", res.a0, res.a1, res.a2, res.a3); > > + GUEST_DONE(); > > +} > > + > > +int main (int argc, char *argv[]) > > +{ > > + struct kvm_vcpu *vcpu; > > + struct kvm_vm *vm; > > + struct ucall uc; > > + bool guest_done = false; > > + > > + vm = vm_create_with_one_vcpu(&vcpu, guest_code); > > + > > + while (!guest_done) { > > + vcpu_run(vcpu); > > + > > + switch (get_ucall(vcpu, &uc)) { > > + case UCALL_SYNC: > > + break; > > + case UCALL_DONE: > > + guest_done = true; > > + break; > > + case UCALL_ABORT: > > + REPORT_GUEST_ASSERT(uc); > > + break; > > + case UCALL_PRINTF: > > + printf("%s", uc.buffer); > > + break; > > + default: > > + TEST_FAIL("Unexpected guest exit"); > > + } > > + } > > This is becoming a very common and useful pattern. I wonder if it's time > for a ucall helper > > static void ucall_vcpu_run(struct kvm_vcpu *vcpu, > void (*sync_func)(struct kvm_vcpu *, void *), > void *sync_data) > { > bool guest_done = false; > struct ucall uc; > > while (!guest_done) { > vcpu_run(vcpu); > > switch (get_ucall(vcpu, &uc)) { > case UCALL_SYNC: > if (sync_func) > sync_func(vcpu, sync_data); > break; > case UCALL_DONE: > guest_done = true; > break; > case UCALL_ABORT: > REPORT_GUEST_ASSERT(uc); > break; > case UCALL_PRINTF: > printf("%s", uc.buffer); > break; > default: > TEST_FAIL("Unexpected guest exit"); > } > } > } Honestly, I don't know. My understanding is that the common kvm selftest code is now mostly a pile of x86-specific stuff, and I've made it a goal not to touch any of it. Thanks, M. -- Without deviation from the norm, progress is not possible.