RE: [PATCH] KVM: vmx: fix a build warning in hv_enable_direct_tlbflush() on i386

Tianyu Lan
2019-09-25T09:05:01Z

There is another warning in the report.

arch/x86/kvm/vmx/vmx.c: In function 'hv_enable_direct_tlbflush':
arch/x86/kvm/vmx/vmx.c:507:20: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
evmcs->hv_vm_id = (u64)vcpu->kvm;
^
The following change can fix it.
- evmcs->hv_vm_id = (u64)vcpu->kvm;
+ evmcs->hv_vm_id = (unsigned long)vcpu->kvm;
evmcs->hv_enlightenments_control.nested_flush_hypercall = 1;

-----Original Message-----
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Sent: Wednesday, September 25, 2019 4:53 PM
To: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org; Paolo Bonzini <pbonzini@redhat.com>; Radim Krčmář <rkrcmar@redhat.com>; Sean Christopherson <sean.j.christopherson@intel.com>; Jim Mattson <jmattson@google.com>; Tianyu Lan <Tianyu.Lan@microsoft.com>
Subject: [PATCH] KVM: vmx: fix a build warning in hv_enable_direct_tlbflush() on i386

The following was reported on i386:

arch/x86/kvm/vmx/vmx.c: In function 'hv_enable_direct_tlbflush':
arch/x86/kvm/vmx/vmx.c:503:10: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]

The particular pr_debug() causing it is more or less useless, let's just remove it. Also, simplify the condition a little bit.

Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/kvm/vmx/vmx.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index a7c9922e3905..812553b7270f 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -495,13 +495,11 @@ static int hv_enable_direct_tlbflush(struct kvm_vcpu *vcpu)
* Synthetic VM-Exit is not enabled in current code and so All
* evmcs in singe VM shares same assist page.
*/
- if (!*p_hv_pa_pg) {
+ if (!*p_hv_pa_pg)
*p_hv_pa_pg = kzalloc(PAGE_SIZE, GFP_KERNEL);
- if (!*p_hv_pa_pg)
- return -ENOMEM;
- pr_debug("KVM: Hyper-V: allocated PA_PG for %llx\n",
- (u64)&vcpu->kvm);
- }
+
+ if (!*p_hv_pa_pg)
+ return -ENOMEM;

evmcs = (struct hv_enlightened_vmcs *)to_vmx(vcpu)->loaded_vmcs->vmcs;

--
2.20.1