linux-kernel - [PATCH 08/18] Drivers: hv: vmbus: Move the check for hypercall page setup

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Message-Id: <1483133772-29776-8-git-send-email-kys@exchange.microsoft.com>
Date:   Fri, 30 Dec 2016 13:36:02 -0800
From:   kys@...hange.microsoft.com
To:     gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
        devel@...uxdriverproject.org, olaf@...fle.de, apw@...onical.com,
        vkuznets@...hat.com, jasowang@...hat.com,
        leann.ogasawara@...onical.com, rkagan@...tuozzo.com,
        x86@...nel.org, tglx@...utronix.de, hpa@...or.com
Cc:     "K. Y. Srinivasan" <kys@...rosoft.com>
Subject: [PATCH 08/18] Drivers: hv: vmbus: Move the check for hypercall page setup

From: K. Y. Srinivasan <kys@...rosoft.com>

As part of the effort to separate out architecture specific code, move the
check for detecting if the hypercall page is setup.

Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
---
 arch/x86/hyperv/hv_init.c       |   15 +++++++++++++++
 arch/x86/include/asm/mshyperv.h |    1 +
 drivers/hv/hv.c                 |    7 +------
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 299cafb..8c14488 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -234,3 +234,18 @@ void hyperv_report_panic(struct pt_regs *regs)
 	wrmsrl(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
 }
 EXPORT_SYMBOL_GPL(hyperv_report_panic);
+
+bool hv_is_hypercall_page_setup(void)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+
+	/* Check if the hypercall page is setup */
+	hypercall_msr.as_uint64 = 0;
+	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	if (!hypercall_msr.enable)
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(hv_is_hypercall_page_setup);
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 64e682d..c843ef6 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -115,5 +115,6 @@ static inline  __u64 generate_guest_id(__u64 d_info1, __u64 kernel_version,
 #if IS_ENABLED(CONFIG_HYPERV)
 void hyperv_init(void);
 void hyperv_report_panic(struct pt_regs *regs);
+bool hv_is_hypercall_page_setup(void);
 #endif
 #endif
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 55b85c3..9021398 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -49,7 +49,6 @@ struct hv_context hv_context = {
  */
 int hv_init(void)
 {
-	union hv_x64_msr_hypercall_contents hypercall_msr;
 
 	memset(hv_context.synic_event_page, 0, sizeof(void *) * NR_CPUS);
 	memset(hv_context.synic_message_page, 0,
@@ -65,11 +64,7 @@ int hv_init(void)
 	memset(hv_context.clk_evt, 0,
 	       sizeof(void *) * NR_CPUS);
 
-	/* See if the hypercall page is already set */
-	hypercall_msr.as_uint64 = 0;
-	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
-
-	if (!hypercall_msr.enable)
+	if (!hv_is_hypercall_page_setup())
 		return -ENOTSUPP;
 
 	return 0;
-- 
1.7.4.1