From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Michal Luczaj <mhal@rbox.co>,
David Woodhouse <dwmw2@infradead.org>
Subject: [PATCH v2 16/16] KVM: selftests: Mark "guest_saw_irq" as volatile in xen_shinfo_test
Date: Thu, 13 Oct 2022 21:12:34 +0000 [thread overview]
Message-ID: <20221013211234.1318131-17-seanjc@google.com> (raw)
In-Reply-To: <20221013211234.1318131-1-seanjc@google.com>
Tag "guest_saw_irq" as "volatile" to ensure that the compiler will never
optimize away lookups. Relying on the compiler thinking that the flag
is global and thus might change also works, but it's subtle, less robust,
and looks like a bug at first glance, e.g. risks being "fixed" and
breaking the test.
Make the flag "static" as well since convincing the compiler it's global
is no longer necessary.
Alternatively, the flag could be accessed with {READ,WRITE}_ONCE(), but
literally every access would need the wrappers, and eking out performance
isn't exactly top priority for selftests.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c b/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c
index caa3f5ab9e10..2a5727188c8d 100644
--- a/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c
+++ b/tools/testing/selftests/kvm/x86_64/xen_shinfo_test.c
@@ -132,7 +132,7 @@ struct {
struct kvm_irq_routing_entry entries[2];
} irq_routes;
-bool guest_saw_irq;
+static volatile bool guest_saw_irq;
static void evtchn_handler(struct ex_regs *regs)
{
--
2.38.0.413.g74048e4d9e-goog
prev parent reply other threads:[~2022-10-13 21:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-13 21:12 [PATCH v2 00/16] KVM: x86: gfn_to_pfn_cache fixes and cleanups Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 01/16] KVM: Initialize gfn_to_pfn_cache locks in dedicated helper Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 02/16] KVM: Reject attempts to consume or refresh inactive gfn_to_pfn_cache Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 03/16] KVM: x86: Always use non-compat vcpu_runstate_info size for gfn=>pfn cache Sean Christopherson
2022-10-27 11:11 ` Paolo Bonzini
2022-10-27 14:44 ` Sean Christopherson
2022-10-27 15:03 ` Paolo Bonzini
2022-10-27 15:10 ` Sean Christopherson
2022-10-27 16:56 ` Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 04/16] KVM: Shorten gfn_to_pfn_cache function names Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 05/16] KVM: x86: Remove unused argument in gpc_unmap_khva() Sean Christopherson
2022-12-02 9:28 ` Like Xu
2022-12-02 10:57 ` Michal Luczaj
2022-12-02 14:21 ` David Woodhouse
2022-12-02 17:01 ` Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 06/16] KVM: Store immutable gfn_to_pfn_cache properties Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 07/16] KVM: Store gfn_to_pfn_cache length as an immutable property Sean Christopherson
2022-11-21 14:26 ` David Woodhouse
2022-11-21 19:11 ` Sean Christopherson
2022-11-21 20:02 ` David Woodhouse
2022-11-22 18:59 ` Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 08/16] KVM: Use gfn_to_pfn_cache's immutable "kvm" in kvm_gpc_check() Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 09/16] KVM: Clean up hva_to_pfn_retry() Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 10/16] KVM: Use gfn_to_pfn_cache's immutable "kvm" in kvm_gpc_refresh() Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 11/16] KVM: Drop KVM's API to allow temprorarily unmapping gfn=>pfn cache Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 12/16] KVM: Do not partially reinitialize gfn=>pfn cache during activation Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 13/16] KVM: Drop @gpa from exported gfn=>pfn cache check() and refresh() helpers Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 14/16] KVM: Skip unnecessary "unmap" if gpc is already valid during refresh Sean Christopherson
2022-10-13 21:12 ` [PATCH v2 15/16] KVM: selftests: Add tests in xen_shinfo_test to detect lock races Sean Christopherson
2022-10-13 21:12 ` Sean Christopherson [this message]
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=20221013211234.1318131-17-seanjc@google.com \
--to=seanjc@google.com \
--cc=dwmw2@infradead.org \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mhal@rbox.co \
--cc=pbonzini@redhat.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