linux-kernel - Re: [PATCH v3 1/4] KVM: x86: Move kvm_ops_static_call

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 29 Mar 2022 23:26:25 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Like Xu <like.xu.linux@...il.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        Jim Mattson <jmattson@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/4] KVM: x86: Move kvm_ops_static_call_update() to
 x86.c

On Tue, Mar 29, 2022, Sean Christopherson wrote:
> On Mon, Mar 07, 2022, Like Xu wrote:
> > From: Like Xu <likexu@...cent.com>
> > 
> > The kvm_ops_static_call_update() is defined in kvm_host.h. That's
> > completely unnecessary, it should have exactly one caller,
> > kvm_arch_hardware_setup().  As a prep match, move
> > kvm_ops_static_call_update() to x86.c, then it can reference
> > the kvm_pmu_ops stuff.
> > 
> > Suggested-by: Sean Christopherson <seanjc@...gle.com>
> > Signed-off-by: Like Xu <likexu@...cent.com>
> > ---
> 
> Reviewed-by: Sean Christopherson <seanjc@...gle.com>

Actually, I take that back.  If we pass in @ops, and do some other minor tweaks
along the way, then we can make kvm_pmu_ops static.

I'll post a very compile-tested-only v3.1, trying to generate diffs against your
series is going to be painful due to conflicts.  The changes aren't big, just
annoying.

Below is the diff for this patch.  Then in patch 2, kvm_ops_update() adds a call
to kvm_pmu_ops_update().  Patch 3 just tweaks the call to use ops->pmu_ops instead
of ops->runtime_ops->pmu_ops.  Patch 4 becomes purely code shuffling (I think).

---
 arch/x86/kvm/x86.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9cb8672aab92..99aa2d16845a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11595,8 +11595,10 @@ void kvm_arch_hardware_disable(void)
 	drop_user_return_notifiers();
 }

-static inline void kvm_ops_static_call_update(void)
+static inline void kvm_ops_update(struct kvm_x86_init_ops *ops)
 {
+	memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
+
 #define __KVM_X86_OP(func) \
 	static_call_update(kvm_x86_##func, kvm_x86_ops.func);
 #define KVM_X86_OP(func) \
@@ -11623,8 +11625,7 @@ int kvm_arch_hardware_setup(void *opaque)
 	if (r != 0)
 		return r;

-	memcpy(&kvm_x86_ops, ops->runtime_ops, sizeof(kvm_x86_ops));
-	kvm_ops_static_call_update();
+	kvm_ops_update(ops);

 	kvm_register_perf_callbacks(ops->handle_intel_pt_intr);


base-commit: bd6b09f0754bea388a189d544ce11d83206579a2
--