KVM: arm64: Restructure FGT register switching

As we're about to majorly extend the handling of FGT registers,
restructure the code to actually save/restore the registers
as required. This is made easy thanks to the previous addition
of the EL2 registers, allowing us to use the host context for
this purpose.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230815183903.2735724-14-maz@kernel.org

1 files changed, 21 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h
index 028049b147df..85908aa18908 100644
--- a/arch/arm64/include/asm/kvm_arm.h
+++ b/arch/arm64/include/asm/kvm_arm.h
@@ -333,6 +333,27 @@
 				 BIT(18) |		\
 				 GENMASK(16, 15))
 
+/*
+ * FGT register definitions
+ *
+ * RES0 and polarity masks as of DDI0487J.a, to be updated as needed.
+ * We're not using the generated masks as they are usually ahead of
+ * the published ARM ARM, which we use as a reference.
+ *
+ * Once we get to a point where the two describe the same thing, we'll
+ * merge the definitions. One day.
+ */
+#define __HFGRTR_EL2_RES0	(GENMASK(63, 56) | GENMASK(53, 51))
+#define __HFGRTR_EL2_MASK	GENMASK(49, 0)
+#define __HFGRTR_EL2_nMASK	(GENMASK(55, 54) | BIT(50))
+
+#define __HFGWTR_EL2_RES0	(GENMASK(63, 56) | GENMASK(53, 51) |	\
+				 BIT(46) | BIT(42) | BIT(40) | BIT(28) | \
+				 GENMASK(26, 25) | BIT(21) | BIT(18) |	\
+				 GENMASK(15, 14) | GENMASK(10, 9) | BIT(2))
+#define __HFGWTR_EL2_MASK	GENMASK(49, 0)
+#define __HFGWTR_EL2_nMASK	(GENMASK(55, 54) | BIT(50))
+
 /* Hyp Prefetch Fault Address Register (HPFAR/HDFAR) */
 #define HPFAR_MASK	(~UL(0xf))
 /*