KVM: PPC: Book3S HV: Don't access XIVE PIPR register using byte accesses

The XIVE interrupt controller on POWER9 machines doesn't support byte
accesses to any register in the thread management area other than the
CPPR (current processor priority register).  In particular, when
reading the PIPR (pending interrupt priority register), we need to
do a 32-bit or 64-bit load.

Cc: stable@vger.kernel.org # v4.13
Fixes: 2c4fb78f78b6 ("KVM: PPC: Book3S HV: Workaround POWER9 DD1.0 bug causing IPB bit loss")
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

3 files changed, 4 insertions, 5 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_rm_xive.c b/arch/powerpc/kvm/book3s_hv_rm_xive.c
index abf5f01b6eb1..5b81a807d742 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_xive.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_xive.c
@@ -38,7 +38,6 @@ static inline void __iomem *get_tima_phys(void)
 #define __x_tima                get_tima_phys()
 #define __x_eoi_page(xd)        ((void __iomem *)((xd)->eoi_page))
 #define __x_trig_page(xd)       ((void __iomem *)((xd)->trig_page))
-#define __x_readb       __raw_rm_readb
 #define __x_writeb      __raw_rm_writeb
 #define __x_readw       __raw_rm_readw
 #define __x_readq       __raw_rm_readq
diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
index 08b200a0bbce..13304622ab1c 100644
--- a/arch/powerpc/kvm/book3s_xive.c
+++ b/arch/powerpc/kvm/book3s_xive.c
@@ -48,7 +48,6 @@
 #define __x_tima                xive_tima
 #define __x_eoi_page(xd)        ((void __iomem *)((xd)->eoi_mmio))
 #define __x_trig_page(xd)       ((void __iomem *)((xd)->trig_mmio))
-#define __x_readb       __raw_readb
 #define __x_writeb      __raw_writeb
 #define __x_readw       __raw_readw
 #define __x_readq       __raw_readq
diff --git a/arch/powerpc/kvm/book3s_xive_template.c b/arch/powerpc/kvm/book3s_xive_template.c
index d1ed2c41b5d2..c7a5deadd1cc 100644
--- a/arch/powerpc/kvm/book3s_xive_template.c
+++ b/arch/powerpc/kvm/book3s_xive_template.c
@@ -28,7 +28,8 @@ static void GLUE(X_PFX,ack_pending)(struct kvmppc_xive_vcpu *xc)
          * bit.
          */
         if (cpu_has_feature(CPU_FTR_POWER9_DD1)) {
-                u8 pipr = __x_readb(__x_tima + TM_QW1_OS + TM_PIPR);
+                __be64 qw1 = __x_readq(__x_tima + TM_QW1_OS);
+                u8 pipr = be64_to_cpu(qw1) & 0xff;
                 if (pipr >= xc->hw_cppr)
                         return;
         }
@@ -336,7 +337,6 @@ X_STATIC unsigned long GLUE(X_PFX,h_ipoll)(struct kvm_vcpu *vcpu, unsigned long
         struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
         u8 pending = xc->pending;
         u32 hirq;
-        u8 pipr;
 
         pr_devel("H_IPOLL(server=%ld)\n", server);
 
@@ -353,7 +353,8 @@ X_STATIC unsigned long GLUE(X_PFX,h_ipoll)(struct kvm_vcpu *vcpu, unsigned long
                 pending = 0xff;
         } else {
                 /* Grab pending interrupt if any */
-                pipr = __x_readb(__x_tima + TM_QW1_OS + TM_PIPR);
+                __be64 qw1 = __x_readq(__x_tima + TM_QW1_OS);
+                u8 pipr = be64_to_cpu(qw1) & 0xff;
                 if (pipr < 8)
                         pending |= 1 << pipr;
         }