[PATCH] lib: sbi: Fix GPA passed to __sbi_hfence_gvma_xyz() functions

[Anup Patel]

The parameter passed to HFENCE.GVMA instruction in rs1 register
is guest physical address right shifted by 2 (i.e. divided by 4).

Unfortunately, we overlooked the semantics of rs1 registers for
HFENCE.GVMA instruction and never right shifted guest physical
address by 2. This issue did not manifest for hypervisors till
now because all H-extension implementations (such as QEMU, Spike,
Rocket Core FPGA, etc) we tried till now were conservatively
flushing everything upon any HFENCE.GVMA instruction.

This patch fixes GPA passed to __sbi_hfence_gvma_vmid_gpa()
and __sbi_hfence_gvma_gpa() functions.

Fixes: 331ff6a162c1 ("lib: Support stage1 and stage2 tlb flushing")
Reported-by: Ian Huang <ihuang at ventanamicro.com>
Signed-off-by: Anup Patel <anup.patel at wdc.com>
---
 include/sbi/sbi_hfence.h | 5 +++--
 lib/sbi/sbi_hfence.S     | 4 ++--
 lib/sbi/sbi_tlb.c        | 4 ++--
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/include/sbi/sbi_hfence.h b/include/sbi/sbi_hfence.h
index 4420f27..d3958f1 100644
--- a/include/sbi/sbi_hfence.h
+++ b/include/sbi/sbi_hfence.h
@@ -12,13 +12,14 @@
 #define __SBI_FENCE_H__
 
 /** Invalidate Stage2 TLBs for given VMID and guest physical address */
-void __sbi_hfence_gvma_vmid_gpa(unsigned long gpa, unsigned long vmid);
+void __sbi_hfence_gvma_vmid_gpa(unsigned long gpa_divby_4,
+				unsigned long vmid);
 
 /** Invalidate Stage2 TLBs for given VMID */
 void __sbi_hfence_gvma_vmid(unsigned long vmid);
 
 /** Invalidate Stage2 TLBs for given guest physical address */
-void __sbi_hfence_gvma_gpa(unsigned long gpa);
+void __sbi_hfence_gvma_gpa(unsigned long gpa_divby_4);
 
 /** Invalidate all possible Stage2 TLBs */
 void __sbi_hfence_gvma_all(void);
diff --git a/lib/sbi/sbi_hfence.S b/lib/sbi/sbi_hfence.S
index d05becb..e11e650 100644
--- a/lib/sbi/sbi_hfence.S
+++ b/lib/sbi/sbi_hfence.S
@@ -27,7 +27,7 @@
 	.global __sbi_hfence_gvma_vmid_gpa
 __sbi_hfence_gvma_vmid_gpa:
 	/*
-	 * rs1 = a0 (GPA)
+	 * rs1 = a0 (GPA >> 2)
 	 * rs2 = a1 (VMID)
 	 * HFENCE.GVMA a0, a1
 	 * 0110001 01011 01010 000 00000 1110011
@@ -51,7 +51,7 @@ __sbi_hfence_gvma_vmid:
 	.global __sbi_hfence_gvma_gpa
 __sbi_hfence_gvma_gpa:
 	/*
-	 * rs1 = a0 (GPA)
+	 * rs1 = a0 (GPA >> 2)
 	 * rs2 = zero
 	 * HFENCE.GVMA a0
 	 * 0110001 00000 01010 000 00000 1110011
diff --git a/lib/sbi/sbi_tlb.c b/lib/sbi/sbi_tlb.c
index efa74a7..4c142ea 100644
--- a/lib/sbi/sbi_tlb.c
+++ b/lib/sbi/sbi_tlb.c
@@ -72,7 +72,7 @@ void sbi_tlb_local_hfence_gvma(struct sbi_tlb_info *tinfo)
 	}
 
 	for (i = 0; i < size; i += PAGE_SIZE) {
-		__sbi_hfence_gvma_gpa(start+i);
+		__sbi_hfence_gvma_gpa((start + i) >> 2);
 	}
 }
 
@@ -148,7 +148,7 @@ void sbi_tlb_local_hfence_gvma_vmid(struct sbi_tlb_info *tinfo)
 	}
 
 	for (i = 0; i < size; i += PAGE_SIZE) {
-		__sbi_hfence_gvma_vmid_gpa(start + i, vmid);
+		__sbi_hfence_gvma_vmid_gpa((start + i) >> 2, vmid);
 	}
 }
 
-- 
2.25.1