linux-kernel - [PATCH 3.14 38/51] arm64: KVM: allows discrimination of AArch32 sysreg access

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Message-Id: <20150515230951.829540813@linuxfoundation.org>
Date:	Fri, 15 May 2015 16:10:40 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Marc Zyngier <marc.zyngier@....com>,
	Christoffer Dall <christoffer.dall@...aro.org>,
	Shannon Zhao <shannon.zhao@...aro.org>
Subject: [PATCH 3.14 38/51] arm64: KVM: allows discrimination of AArch32 sysreg access

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marc Zyngier <marc.zyngier@....com>

commit 2072d29c46b73e39b3c6c56c6027af77086f45fd upstream.

The current handling of AArch32 trapping is slightly less than
perfect, as it is not possible (from a handler point of view)
to distinguish it from an AArch64 access, nor to tell a 32bit
from a 64bit access either.

Fix this by introducing two additional flags:
- is_aarch32: true if the access was made in AArch32 mode
- is_32bit: true if is_aarch32 == true and a MCR/MRC instruction
  was used to perform the access (as opposed to MCRR/MRRC).

This allows a handler to cover all the possible conditions in which
a system register gets trapped.

Signed-off-by: Marc Zyngier <marc.zyngier@....com>
Acked-by: Christoffer Dall <christoffer.dall@...aro.org>
Cc: Shannon Zhao <shannon.zhao@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm64/kvm/sys_regs.c |    6 ++++++
 arch/arm64/kvm/sys_regs.h |    2 ++
 2 files changed, 8 insertions(+)

--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -437,6 +437,8 @@ int kvm_handle_cp15_64(struct kvm_vcpu *
 	u32 hsr = kvm_vcpu_get_hsr(vcpu);
 	int Rt2 = (hsr >> 10) & 0xf;
 
+	params.is_aarch32 = true;
+	params.is_32bit = false;
 	params.CRm = (hsr >> 1) & 0xf;
 	params.Rt = (hsr >> 5) & 0xf;
 	params.is_write = ((hsr & 1) == 0);
@@ -480,6 +482,8 @@ int kvm_handle_cp15_32(struct kvm_vcpu *
 	struct sys_reg_params params;
 	u32 hsr = kvm_vcpu_get_hsr(vcpu);
 
+	params.is_aarch32 = true;
+	params.is_32bit = true;
 	params.CRm = (hsr >> 1) & 0xf;
 	params.Rt  = (hsr >> 5) & 0xf;
 	params.is_write = ((hsr & 1) == 0);
@@ -549,6 +553,8 @@ int kvm_handle_sys_reg(struct kvm_vcpu *
 	struct sys_reg_params params;
 	unsigned long esr = kvm_vcpu_get_hsr(vcpu);
 
+	params.is_aarch32 = false;
+	params.is_32bit = false;
 	params.Op0 = (esr >> 20) & 3;
 	params.Op1 = (esr >> 14) & 0x7;
 	params.CRn = (esr >> 10) & 0xf;
--- a/arch/arm64/kvm/sys_regs.h
+++ b/arch/arm64/kvm/sys_regs.h
@@ -30,6 +30,8 @@ struct sys_reg_params {
 	u8	Op2;
 	u8	Rt;
 	bool	is_write;
+	bool	is_aarch32;
+	bool	is_32bit;	/* Only valid if is_aarch32 is true */
 };
 
 struct sys_reg_desc {


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