linux-kernel - [PATCH] x86/hyperv: Restrict get

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Message-Id: <1694604531-17128-1-git-send-email-ssengar@linux.microsoft.com>
Date:   Wed, 13 Sep 2023 04:28:51 -0700
From:   Saurabh Sengar <ssengar@...ux.microsoft.com>
To:     kys@...rosoft.com, haiyangz@...rosoft.com, wei.liu@...nel.org,
        decui@...rosoft.com, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org,
        hpa@...or.com, linux-hyperv@...r.kernel.org,
        linux-kernel@...r.kernel.org, mikelley@...rosoft.com
Cc:     ssengar@...rosoft.com
Subject: [PATCH] x86/hyperv: Restrict get_vtl to only VTL platforms

For non VTL platforms vtl is always 0, and there is no need of
get_vtl function. For VTL platforms get_vtl should always succeed
and should return the correct VTL.

Signed-off-by: Saurabh Sengar <ssengar@...ux.microsoft.com>
---
 arch/x86/hyperv/hv_init.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 783ed339f341..e589c240565a 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -416,8 +416,8 @@ static u8 __init get_vtl(void)
 	if (hv_result_success(ret)) {
 		ret = output->as64.low & HV_X64_VTL_MASK;
 	} else {
-		pr_err("Failed to get VTL(%lld) and set VTL to zero by default.\n", ret);
-		ret = 0;
+		pr_err("Failed to get VTL(error: %lld) exiting...\n", ret);
+		BUG();
 	}
 
 	local_irq_restore(flags);
@@ -604,8 +604,10 @@ void __init hyperv_init(void)
 	hv_query_ext_cap(0);
 
 	/* Find the VTL */
-	if (!ms_hyperv.paravisor_present && hv_isolation_type_snp())
+	if (IS_ENABLED(CONFIG_HYPERV_VTL_MODE))
 		ms_hyperv.vtl = get_vtl();
+	else
+		ms_hyperv.vtl = 0;
 
 	return;
 
-- 
2.34.1