From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 15E4033F5B6; Thu, 18 Jun 2026 19:06:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781809575; cv=none; b=YjMLqgHWzS0JOcxiwA5ywkJLQVjg7zzkYf3Ks7wE9pg6qMQHRW+PkvNCa9FPodq4mBjjr15m19cKSfWt3CYL0u2LwTVpYVzpyB6ZMTDUr/PTAdty59MB2gaKGMVjVVrxZE8HZ0t8aWv0oRZn4fYwhdYwZaQ9RTligTARjUNHdtA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781809575; c=relaxed/simple; bh=1Tv0YmVhkx8ud0qt22F8mlihvisOlxy+ZlCpIP1c5vE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ml92Wb4hae3YMHf0hkQe6w94XZkTgLxl9u82DfMdCKcclfxHeTK5e/x+809W09AaXKh6qIKe6zq4jzALaJES9R9Gcu+rjgSTZbAoNluTHOVQ6lExlm1UFcgC5xp1U1kv8BF0GiJvYclPq4IYqJ79QWnMgbDX8w+IaWBwNE43kC8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QJFYo1fH; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QJFYo1fH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8C0601F000E9; Thu, 18 Jun 2026 19:06:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781809573; bh=wR6Mtq5nZ+5UapL5g8Gruh6bzm0GAsMPkKV4VGUnpD0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=QJFYo1fHYvc3pXPSZSAyFDU4Z0SNbW8oFKZ8rnOuhLSFy9g3a3hdDVJ/DyK45vkU/ o7sj9BqU7NRvNOIfnVx+H9IhJRHLBnrCTnoGe+MWP+++QpUbpxQ/NB+6eySUFtDWQP fXtMJCCjGqSYFIjJqcXXpVVTGolsmDvW3Pf961XCU1S0IYWcU0rsR5xFV++L+mNbad 29wz1z0MgzqDfYbDN/ppBvt+4vcqPHX2uK6nilp6uRIhZ+nRyQMDEooNftiA7d6ejd vi4YMnbwPcLAeTtRHfk8uAzNTofi6LAi2y5dSiC4Jqb2MwQjeq0Yb2AFJHeW3kLZGa skCgxmdzudOGQ== Date: Thu, 18 Jun 2026 12:06:12 -0700 From: Oliver Upton To: Alexandru Elisei Cc: will@kernel.org, julien.thierry.kdev@gmail.com, maz@kernel.org, jean-philippe.brucker@arm.com, andre.przywara@arm.com, suzuki.poulose@arm.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Subject: Re: [PATCH kvmtool v2 7/7] arm64: Improve KVM_ARM_VCPU_PMU_V3_CTRL diagnostics Message-ID: References: <20260618155001.226266-1-alexandru.elisei@arm.com> <20260618155001.226266-8-alexandru.elisei@arm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260618155001.226266-8-alexandru.elisei@arm.com> On Thu, Jun 18, 2026 at 04:50:01PM +0100, Alexandru Elisei wrote: > kvmtool issues several ioctls when configuring the PMU, and each of them > can fail for different reasons. Be more specific about the ioctl that > failed when that happens. > > Signed-off-by: Alexandru Elisei > --- > arm64/pmu.c | 31 ++++++++++++++++++++++++------- > 1 file changed, 24 insertions(+), 7 deletions(-) > > diff --git a/arm64/pmu.c b/arm64/pmu.c > index 92cacd62479e..78c15f153fad 100644 > --- a/arm64/pmu.c > +++ b/arm64/pmu.c > @@ -12,6 +12,24 @@ > > #include "asm/pmu.h" > > +static const char *pmu_attr_names[] = { > + [KVM_ARM_VCPU_PMU_V3_IRQ] = "KVM_ARM_VCPU_PMU_V3_IRQ", > + [KVM_ARM_VCPU_PMU_V3_INIT] = "KVM_ARM_VCPU_PMU_V3_INIT", > + [KVM_ARM_VCPU_PMU_V3_FILTER] = "KVM_ARM_VCPU_PMU_V3_FILTER", > + [KVM_ARM_VCPU_PMU_V3_SET_PMU] = "KVM_ARM_VCPU_PMU_V3_SET_PMU", > + [KVM_ARM_VCPU_PMU_V3_SET_NR_COUNTERS] = "KVM_ARM_VCPU_PMU_V3_SET_NR_COUNTER", > +}; > + > +static const char *pmu_get_attr_name(u64 attr) > +{ > + switch (attr) { > + case KVM_ARM_VCPU_PMU_V3_IRQ ... KVM_ARM_VCPU_PMU_V3_SET_NR_COUNTERS: > + return pmu_attr_names[attr]; > + default: > + return "UNKNOWN"; > + } > +} > + > static bool pmu_has_attr(struct kvm_cpu *vcpu, u64 attr) > { > struct kvm_device_attr pmu_attr = { > @@ -32,13 +50,12 @@ static void set_pmu_attr(struct kvm_cpu *vcpu, void *addr, u64 attr) > }; > int ret; > > - if (pmu_has_attr(vcpu, attr)) { > - ret = ioctl(vcpu->vcpu_fd, KVM_SET_DEVICE_ATTR, &pmu_attr); > - if (ret) > - die_perror("PMU KVM_SET_DEVICE_ATTR"); > - } else { > - die_perror("PMU KVM_HAS_DEVICE_ATTR"); > - } > + if (!pmu_has_attr(vcpu, attr)) > + die_perror("KVM_HAS_DEVICE_ATTR(%s)", pmu_get_attr_name(attr)); > + > + ret = ioctl(vcpu->vcpu_fd, KVM_SET_DEVICE_ATTR, &pmu_attr); > + if (ret) > + die_perror("KVM_SET_DEVICE_ATTR(%s)", pmu_get_attr_name(attr)); > } The whole if (ret) die_perror(...) thing is a bit repetetive IMO. A treewide cleanup replacing this with macros would be nice, then you could stringize the ioctl under the hood. diff --git a/arm64/pmu.c b/arm64/pmu.c index 5f31d6b..0d9f3df 100644 --- a/arm64/pmu.c +++ b/arm64/pmu.c @@ -23,23 +23,19 @@ static bool pmu_has_attr(struct kvm_cpu *vcpu, u64 attr) return ret == 0; } -static void set_pmu_attr(struct kvm_cpu *vcpu, void *addr, u64 attr) -{ - struct kvm_device_attr pmu_attr = { - .group = KVM_ARM_VCPU_PMU_V3_CTRL, - .addr = (u64)addr, - .attr = attr, - }; - int ret; - - if (pmu_has_attr(vcpu, attr)) { - ret = ioctl(vcpu->vcpu_fd, KVM_SET_DEVICE_ATTR, &pmu_attr); - if (ret) - die_perror("PMU KVM_SET_DEVICE_ATTR"); - } else { - die_perror("PMU KVM_HAS_DEVICE_ATTR"); - } -} +#define kvm_set_device_attr(fd, _group, _attr, _addr) \ +do { \ + struct kvm_device_attr __attr = { \ + .group = (_group), \ + .attr = (_attr), \ + .addr = (u64)(_addr), \ + }; \ + int r; \ + \ + r = ioctl((fd), KVM_SET_DEVICE_ATTR, &__attr); \ + if (r) \ + die_perror("KVM_SET_DEVICE_ATTR(group:"#_group", attr:"#_attr")"); \ +} while (0) #define SYS_EVENT_SOURCE "/sys/bus/event_source/devices/" /* @@ -218,14 +214,18 @@ void pmu__generate_fdt_nodes(void *fdt, struct kvm *kvm) for (i = 0; i < kvm->nrcpus; i++) { vcpu = kvm->cpus[i]; - set_pmu_attr(vcpu, &irq, KVM_ARM_VCPU_PMU_V3_IRQ); + kvm_set_device_attr(vcpu->vcpu_fd, KVM_ARM_VCPU_PMU_V3_CTRL, + KVM_ARM_VCPU_PMU_V3_IRQ, &irq); /* * PMU IDs 0-5 are reserved; a positive value means a PMU was * found. */ if (pmu_id > 0) - set_pmu_attr(vcpu, &pmu_id, KVM_ARM_VCPU_PMU_V3_SET_PMU); - set_pmu_attr(vcpu, NULL, KVM_ARM_VCPU_PMU_V3_INIT); + kvm_set_device_attr(vcpu->vcpu_fd, KVM_ARM_VCPU_PMU_V3_CTRL, + KVM_ARM_VCPU_PMU_V3_SET_PMU, &pmu_id); + + kvm_set_device_attr(vcpu->vcpu_fd, KVM_ARM_VCPU_PMU_V3_CTRL, + KVM_ARM_VCPU_PMU_V3_INIT, NULL); } _FDT(fdt_begin_node(fdt, "pmu"));