[ZESTY] [PATCH 13/33] KVM: PPC: Book3S HV: Use ASDR for HPT guests on POWER9

[Breno Leitao]

From: Paul Mackerras <paulus at ozlabs.org>

BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1675806

POWER9 adds a register called ASDR (Access Segment Descriptor
Register), which is set by hypervisor data/instruction storage
interrupts to contain the segment descriptor for the address
being accessed, assuming the guest is using HPT translation.
(For radix guests, it contains the guest real address of the
access.)

Thus, for HPT guests on POWER9, we can use this register rather
than looking up the SLB with the slbfee. instruction.

Signed-off-by: Paul Mackerras <paulus at ozlabs.org>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
(cherry picked from commit ef8c640cb9cc865a461827b698fcc55b0ecaa600)
Signed-off-by: Breno Leitao <breno.leitao at gmail.com>
---
 arch/powerpc/kvm/book3s_hv_rmhandlers.S | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 264ac9ad4585..01f4392a284d 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1715,6 +1715,10 @@ kvmppc_hdsi:
 	/* HPTE not found fault or protection fault? */
 	andis.	r0, r6, (DSISR_NOHPTE | DSISR_PROTFAULT)@h
 	beq	1f			/* if not, send it to the guest */
+BEGIN_FTR_SECTION
+	mfspr	r5, SPRN_ASDR		/* on POWER9, use ASDR to get VSID */
+	b	4f
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 	andi.	r0, r11, MSR_DR		/* data relocation enabled? */
 	beq	3f
 	clrrdi	r0, r4, 28
@@ -1791,6 +1795,10 @@ fast_interrupt_c_return:
 kvmppc_hisi:
 	andis.	r0, r11, SRR1_ISI_NOPT at h
 	beq	1f
+BEGIN_FTR_SECTION
+	mfspr	r5, SPRN_ASDR		/* on POWER9, use ASDR to get VSID */
+	b	4f
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 	andi.	r0, r11, MSR_IR		/* instruction relocation enabled? */
 	beq	3f
 	clrrdi	r0, r10, 28
-- 
2.11.0