[xen staging] xen/arm: fix SBDF calculation for vPCI MMIO handlers

[patchbot@xxxxxxx]

commit 3231ddf9dc384a386df43fd1c0a0bcbba9d79569
Author:     Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
AuthorDate: Tue Nov 2 13:20:41 2021 +0200
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Wed Nov 3 18:15:21 2021 +0000

    xen/arm: fix SBDF calculation for vPCI MMIO handlers
    
    While in vPCI MMIO trap handlers for the guest PCI host bridge it is not
    enough for SBDF translation to simply call VPCI_ECAM_BDF(info->gpa) as
    the base address may not be aligned in the way that the translation
    always work. If not adjusted with respect to the base address it may not be
    able to properly convert SBDF.
    Fix this by adjusting the gpa with respect to the host bridge base address
    in a way as it is done for x86.
    
    Please note, that this change is not strictly required given the current
    value of GUEST_VPCI_ECAM_BASE which has bits 0 to 27 clear, but could cause
    issues if such value is changed, or when handlers for dom0 ECAM
    regions are added as those will be mapped over existing hardware
    regions that could use non-aligned base addresses.
    
    Fixes: d59168dc05a5 ("xen/arm: Enable the existing x86 virtual PCI support 
for ARM")
    
    Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Release-Acked-by: Ian Jackson <iwj@xxxxxxxxxxxxxx>
---
 xen/arch/arm/vpci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/vpci.c b/xen/arch/arm/vpci.c
index 8f40a0dec6..23f45386f4 100644
--- a/xen/arch/arm/vpci.c
+++ b/xen/arch/arm/vpci.c
@@ -24,7 +24,7 @@ static int vpci_mmio_read(struct vcpu *v, mmio_info_t *info,
     unsigned long data;
 
     /* We ignore segment part and always handle segment 0 */
-    sbdf.sbdf = VPCI_ECAM_BDF(info->gpa);
+    sbdf.sbdf = VPCI_ECAM_BDF(info->gpa - GUEST_VPCI_ECAM_BASE);
 
     if ( vpci_ecam_read(sbdf, ECAM_REG_OFFSET(info->gpa),
                         1U << info->dabt.size, &data) )
@@ -44,7 +44,7 @@ static int vpci_mmio_write(struct vcpu *v, mmio_info_t *info,
     pci_sbdf_t sbdf;
 
     /* We ignore segment part and always handle segment 0 */
-    sbdf.sbdf = VPCI_ECAM_BDF(info->gpa);
+    sbdf.sbdf = VPCI_ECAM_BDF(info->gpa - GUEST_VPCI_ECAM_BASE);
 
     return vpci_ecam_write(sbdf, ECAM_REG_OFFSET(info->gpa),
                            1U << info->dabt.size, r);
--
generated by git-patchbot for /home/xen/git/xen.git#staging