linux-kernel - [PATCHv3 02/11] arm64/kvm: consistently handle host HCR

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Message-Id: <20180417183735.56985-3-mark.rutland@arm.com>
Date:   Tue, 17 Apr 2018 19:37:26 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     arnd@...db.de, catalin.marinas@....com, cdall@...nel.org,
        drjones@...hat.com, kvmarm@...ts.cs.columbia.edu,
        linux-arch@...r.kernel.org, marc.zyngier@....com,
        mark.rutland@....com, ramana.radhakrishnan@....com,
        suzuki.poulose@....com, will.deacon@....com,
        linux-kernel@...r.kernel.org, awallis@...eaurora.org,
        kernel-hardening@...ts.openwall.com
Subject: [PATCHv3 02/11] arm64/kvm: consistently handle host HCR_EL2 flags

In KVM we define the configuration of HCR_EL2 for a VHE HOST in
HCR_HOST_VHE_FLAGS, but we don't ahve a similar definition for the
non-VHE host flags, and open-code HCR_RW. Further, in head.S we
open-code the flags for VHE and non-VHE configurations.

In future, we're going to want to configure more flags for the host, so
lets add a HCR_HOST_NVHE_FLAGS defintion, adn consistently use both
HCR_HOST_VHE_FLAGS and HCR_HOST_NVHE_FLAGS in the kvm code and head.S.

We now use mov_q to generate the HCR_EL2 value, as we use when
configuring other registers in head.S.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Christoffer Dall <cdall@...nel.org>
Cc: Marc Zyngier <marc.zyngier@....com>
Cc: Will Deacon <will.deacon@....com>
Cc: kvmarm@...ts.cs.columbia.edu
---
 arch/arm64/include/asm/kvm_arm.h | 1 +
 arch/arm64/kernel/head.S         | 5 ++---
 arch/arm64/kvm/hyp/switch.c      | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 6dd285e979c9..89b3dda7e3cb 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -86,6 +86,7 @@
 			 HCR_AMO | HCR_SWIO | HCR_TIDCP | HCR_RW | HCR_TLOR | \
 			 HCR_FMO | HCR_IMO)
 #define HCR_VIRT_EXCP_MASK (HCR_VSE | HCR_VI | HCR_VF)
+#define HCR_HOST_NVHE_FLAGS (HCR_RW)
 #define HCR_HOST_VHE_FLAGS (HCR_RW | HCR_TGE | HCR_E2H)
 
 /* TCR_EL2 Registers bits */
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index b0853069702f..651a06b1980f 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -494,10 +494,9 @@ ENTRY(el2_setup)
 #endif
 
 	/* Hyp configuration. */
-	mov	x0, #HCR_RW			// 64-bit EL1
+	mov_q	x0, HCR_HOST_NVHE_FLAGS
 	cbz	x2, set_hcr
-	orr	x0, x0, #HCR_TGE		// Enable Host Extensions
-	orr	x0, x0, #HCR_E2H
+	mov_q	x0, HCR_HOST_VHE_FLAGS
 set_hcr:
 	msr	hcr_el2, x0
 	isb
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index d9645236e474..cdae330e15e9 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -143,7 +143,7 @@ static void __hyp_text __deactivate_traps_nvhe(void)
 	mdcr_el2 |= MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT;
 
 	write_sysreg(mdcr_el2, mdcr_el2);
-	write_sysreg(HCR_RW, hcr_el2);
+	write_sysreg(HCR_HOST_NVHE_FLAGS, hcr_el2);
 	write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
 }
 
-- 
2.11.0