From: David Matlack <dmatlack@google.com>
To: Ben Gardon <bgardon@google.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Paolo Bonzini <pbonzini@redhat.com>, Peter Xu <peterx@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Jim Mattson <jmattson@google.com>,
David Dunn <daviddunn@google.com>,
Jing Zhang <jingzhangos@google.com>,
Junaid Shahid <junaids@google.com>
Subject: Re: [PATCH v3 03/11] KVM: selftests: Test reading a single stat
Date: Tue, 5 Apr 2022 22:24:12 +0000 [thread overview]
Message-ID: <YkzBjF3NyI9fyZad@google.com> (raw)
In-Reply-To: <20220330174621.1567317-4-bgardon@google.com>
On Wed, Mar 30, 2022 at 10:46:13AM -0700, Ben Gardon wrote:
> Retrieve the value of a single stat by name in the binary stats test to
> ensure the kvm_util library functions work.
>
> CC: Jing Zhang <jingzhangos@google.com>
> Signed-off-by: Ben Gardon <bgardon@google.com>
> ---
> .../selftests/kvm/include/kvm_util_base.h | 1 +
> .../selftests/kvm/kvm_binary_stats_test.c | 3 ++
> tools/testing/selftests/kvm/lib/kvm_util.c | 53 +++++++++++++++++++
> 3 files changed, 57 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util_base.h b/tools/testing/selftests/kvm/include/kvm_util_base.h
> index 4783fd1cd4cf..78c4407f36b4 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util_base.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util_base.h
> @@ -402,6 +402,7 @@ void assert_on_unhandled_exception(struct kvm_vm *vm, uint32_t vcpuid);
> int vm_get_stats_fd(struct kvm_vm *vm);
> int vcpu_get_stats_fd(struct kvm_vm *vm, uint32_t vcpuid);
> void dump_vm_stats(struct kvm_vm *vm);
> +uint64_t vm_get_single_stat(struct kvm_vm *vm, const char *stat_name);
>
> uint32_t guest_get_vcpuid(void);
>
> diff --git a/tools/testing/selftests/kvm/kvm_binary_stats_test.c b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
> index afc4701ce8dd..97bde355f105 100644
> --- a/tools/testing/selftests/kvm/kvm_binary_stats_test.c
> +++ b/tools/testing/selftests/kvm/kvm_binary_stats_test.c
> @@ -177,6 +177,9 @@ static void vm_stats_test(struct kvm_vm *vm)
>
> /* Dump VM stats */
> dump_vm_stats(vm);
> +
> + /* Read a single stat. */
> + printf("remote_tlb_flush: %lu\n", vm_get_single_stat(vm, "remote_tlb_flush"));
> }
>
> static void vcpu_stats_test(struct kvm_vm *vm, int vcpu_id)
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index f87df68b150d..9c4574381daa 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -2705,3 +2705,56 @@ void dump_vm_stats(struct kvm_vm *vm)
> close(stats_fd);
> }
>
> +static int vm_get_stat_data(struct kvm_vm *vm, const char *stat_name,
> + uint64_t **data)
> +{
> + struct kvm_stats_desc *stats_desc;
> + struct kvm_stats_header *header;
> + struct kvm_stats_desc *desc;
> + size_t size_desc;
> + int stats_fd;
> + int ret = -EINVAL;
> + int i;
> +
> + *data = NULL;
> +
> + stats_fd = vm_get_stats_fd(vm);
> +
> + header = read_vm_stats_header(stats_fd);
> +
> + stats_desc = read_vm_stats_desc(stats_fd, header);
> +
> + size_desc = stats_desc_size(header);
> +
> + /* Read kvm stats data one by one */
> + for (i = 0; i < header->num_desc; ++i) {
> + desc = (void *)stats_desc + (i * size_desc);
> +
> + if (strcmp(desc->name, stat_name))
> + continue;
> +
> + ret = read_stat_data(stats_fd, header, desc, data);
> + }
> +
> + free(stats_desc);
> + free(header);
> +
> + close(stats_fd);
> +
> + return ret;
> +}
> +
> +uint64_t vm_get_single_stat(struct kvm_vm *vm, const char *stat_name)
> +{
> + uint64_t *data;
> + uint64_t value;
> + int ret;
> +
> + ret = vm_get_stat_data(vm, stat_name, &data);
> + TEST_ASSERT(ret == 1, "Stat %s expected to have 1 element, but has %d",
> + stat_name, ret);
> + value = *data;
> + free(data);
Allocating temporary storage for the data is unnecessary. Just read the
stat directly into &value. You'll need to change read_stat_data() to
accept another parameter that defines the number of elements the caller
wants to read. Otherwise botched stats could trigger a buffer overflow.
> + return value;
> +}
> +
> --
> 2.35.1.1021.g381101b075-goog
>
next prev parent reply other threads:[~2022-04-06 2:47 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-30 17:46 [PATCH v3 00/11] KVM: x86: Add a cap to disable NX hugepages on a VM Ben Gardon
2022-03-30 17:46 ` [PATCH v3 01/11] KVM: selftests: Add vm_alloc_page_table_in_memslot library function Ben Gardon
2022-03-30 17:46 ` [PATCH v3 02/11] KVM: selftests: Dump VM stats in binary stats test Ben Gardon
2022-03-30 18:50 ` Jing Zhang
2022-04-05 22:19 ` David Matlack
2022-04-06 20:37 ` Ben Gardon
2022-04-08 19:51 ` Sean Christopherson
2022-06-30 21:00 ` Mingwei Zhang
2022-07-07 19:48 ` Sean Christopherson
2022-03-30 17:46 ` [PATCH v3 03/11] KVM: selftests: Test reading a single stat Ben Gardon
2022-03-30 18:51 ` Jing Zhang
2022-04-05 22:24 ` David Matlack [this message]
2022-04-06 20:48 ` Ben Gardon
2022-03-30 17:46 ` [PATCH v3 04/11] KVM: selftests: Add memslot parameter to elf_load Ben Gardon
2022-04-05 22:27 ` David Matlack
2022-03-30 17:46 ` [PATCH v3 05/11] KVM: selftests: Improve error message in vm_phy_pages_alloc Ben Gardon
2022-04-05 22:29 ` David Matlack
2022-03-30 17:46 ` [PATCH v3 06/11] KVM: selftests: Add NX huge pages test Ben Gardon
2022-04-05 22:38 ` David Matlack
2022-04-07 16:52 ` Ben Gardon
2022-03-30 17:46 ` [PATCH v3 07/11] KVM: x86/MMU: Factor out updating NX hugepages state for a VM Ben Gardon
2022-04-05 22:40 ` David Matlack
2022-03-30 17:46 ` [PATCH v3 08/11] KVM: x86/MMU: Allow NX huge pages to be disabled on a per-vm basis Ben Gardon
2022-04-05 22:46 ` David Matlack
2022-03-30 17:46 ` [PATCH v3 09/11] KVM: x86: Fix errant brace in KVM capability handling Ben Gardon
2022-03-30 17:46 ` [PATCH v3 10/11] KVM: x86/MMU: Require reboot permission to disable NX hugepages Ben Gardon
2022-03-30 18:02 ` Sean Christopherson
2022-03-30 23:42 ` Ben Gardon
2022-03-30 17:46 ` [PATCH v3 11/11] selftests: KVM: Test disabling NX hugepages on a VM Ben Gardon
2022-04-05 22:55 ` David Matlack
2022-04-07 18:26 ` Ben Gardon
2022-04-07 18:39 ` Ben Gardon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YkzBjF3NyI9fyZad@google.com \
--to=dmatlack@google.com \
--cc=bgardon@google.com \
--cc=daviddunn@google.com \
--cc=jingzhangos@google.com \
--cc=jmattson@google.com \
--cc=junaids@google.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
--cc=peterx@redhat.com \
--cc=seanjc@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).