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[4.14,061/190] KVM: arm64: Make vcpu_cp1x() work on Big Endian hosts

Message ID 20200619141636.628274197@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

gregkh@linuxfoundation.org June 19, 2020, 2:31 p.m. UTC 
From: Marc Zyngier <maz@kernel.org>

commit 3204be4109ad681523e3461ce64454c79278450a upstream.

AArch32 CP1x registers are overlayed on their AArch64 counterparts
in the vcpu struct. This leads to an interesting problem as they
are stored in their CPU-local format, and thus a CP1x register
doesn't "hit" the lower 32bit portion of the AArch64 register on
a BE host.

To workaround this unfortunate situation, introduce a bias trick
in the vcpu_cp1x() accessors which picks the correct half of the
64bit register.

Cc: stable@vger.kernel.org
Reported-by: James Morse <james.morse@arm.com>
Tested-by: James Morse <james.morse@arm.com>
Acked-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/arm64/include/asm/kvm_host.h |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
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Patch

--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -292,8 +292,10 @@  struct kvm_vcpu_arch {
  * CP14 and CP15 live in the same array, as they are backed by the
  * same system registers.
  */
-#define vcpu_cp14(v,r)		((v)->arch.ctxt.copro[(r)])
-#define vcpu_cp15(v,r)		((v)->arch.ctxt.copro[(r)])
+#define CPx_BIAS		IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)
+
+#define vcpu_cp14(v,r)		((v)->arch.ctxt.copro[(r) ^ CPx_BIAS])
+#define vcpu_cp15(v,r)		((v)->arch.ctxt.copro[(r) ^ CPx_BIAS])
 
 #ifdef CONFIG_CPU_BIG_ENDIAN
 #define vcpu_cp15_64_high(v,r)	vcpu_cp15((v),(r))