Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>
Cc:     David Rientjes <rientjes@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        Will Drewry <wad@chromium.org>,
        "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
        "Kleen, Andi" <andi.kleen@intel.com>, x86@kernel.org,
        kvm@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: [RFC 12/16] x86/kvm: Share steal time page with host
Date:   Fri, 22 May 2020 15:52:10 +0300
Message-Id: <20200522125214.31348-13-kirill.shutemov@linux.intel.com>
In-Reply-To: <20200522125214.31348-1-kirill.shutemov@linux.intel.com>
References: <20200522125214.31348-1-kirill.shutemov@linux.intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

struct kvm_steal_time is shared between guest and host. Mark it as
shared.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/x86/kernel/kvm.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index f50d65df4412..b0f445796ed1 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -286,11 +286,15 @@ static void kvm_register_steal_time(void)
 {
 	int cpu = smp_processor_id();
 	struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
+	unsigned long phys;
 
 	if (!has_steal_clock)
 		return;
 
-	wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
+	phys = slow_virt_to_phys(st);
+	if (kvm_mem_protected())
+		kvm_hypercall2(KVM_HC_MEM_SHARE, phys >> PAGE_SHIFT, 1);
+	wrmsrl(MSR_KVM_STEAL_TIME, (phys | KVM_MSR_ENABLED));
 	pr_info("kvm-stealtime: cpu %d, msr %llx\n",
 		cpu, (unsigned long long) slow_virt_to_phys(st));
 }
-- 
2.26.2