From: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>
To: qemu-devel@nongnu.org
Cc: "Marek Marczykowski-Górecki" <marmarek@invisiblethingslab.com>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Anthony Perard" <anthony.perard@citrix.com>,
"Paul Durrant" <paul@xen.org>,
xen-devel@lists.xenproject.org (open list:X86 Xen CPUs)
Subject: [PATCH v2 1/3] hw/xen/xen_pt: Save back data only for declared registers
Date: Tue, 30 Apr 2024 19:33:09 +0200 [thread overview]
Message-ID: <3cc5a7d2e0338112fb87806c813627bdf5dbd2a5.1714498385.git-series.marmarek@invisiblethingslab.com> (raw)
In-Reply-To: <cover.ea761e8c87cc41550b01d6fbc1cd1116af55e288.1714498385.git-series.marmarek@invisiblethingslab.com>
Call pci_default_write_config() in xen_pt_pci_write_config() only for
registers that have matching XenPTRegInfo structure, and do that only after
resolving any custom handlers. This is important for two reasons:
1. XenPTRegInfo has ro_mask which needs to be enforced - Xen-specific
hooks do that on their own (especially xen_pt_*_reg_write()).
2. Not setting value early allows hooks to see the old value too.
If it would be only about the first point, setting PCIDevice.wmask would
probably be sufficient, but given the second point, restructure those
writes.
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
---
v2:
- rewrite commit message, previous one was very misleading
- fix loop saving register values
- fix int overflow when calculating write mask
---
hw/xen/xen_pt.c | 24 +++++++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)
diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
index 3635d1b..cea2e18 100644
--- a/hw/xen/xen_pt.c
+++ b/hw/xen/xen_pt.c
@@ -256,6 +256,7 @@ static void xen_pt_pci_write_config(PCIDevice *d, uint32_t addr,
uint32_t find_addr = addr;
XenPTRegInfo *reg = NULL;
bool wp_flag = false;
+ uint32_t emul_mask = 0, write_val;
if (xen_pt_pci_config_access_check(d, addr, len)) {
return;
@@ -311,7 +312,6 @@ static void xen_pt_pci_write_config(PCIDevice *d, uint32_t addr,
}
memory_region_transaction_begin();
- pci_default_write_config(d, addr, val, len);
/* adjust the read and write value to appropriate CFC-CFF window */
read_val <<= (addr & 3) << 3;
@@ -371,6 +371,9 @@ static void xen_pt_pci_write_config(PCIDevice *d, uint32_t addr,
return;
}
+ emul_mask |= ((1L << (reg->size * 8)) - 1)
+ << ((find_addr & 3) * 8);
+
/* calculate next address to find */
emul_len -= reg->size;
if (emul_len > 0) {
@@ -397,6 +400,25 @@ static void xen_pt_pci_write_config(PCIDevice *d, uint32_t addr,
/* need to shift back before passing them to xen_host_pci_set_block. */
val >>= (addr & 3) << 3;
+ /* store emulated registers after calling their handlers */
+ write_val = val;
+ for (index = 0; index < len; index += emul_len) {
+ emul_len = 0;
+ while (emul_mask & 0xff) {
+ emul_len++;
+ emul_mask >>= 8;
+ }
+ if (emul_len) {
+ uint32_t mask = ((1L << (emul_len * 8)) - 1);
+ pci_default_write_config(d, addr + index, write_val & mask,
+ emul_len);
+ } else {
+ emul_mask >>= 8;
+ emul_len = 1;
+ }
+ write_val >>= emul_len * 8;
+ }
+
memory_region_transaction_commit();
out:
--
git-series 0.9.1
next parent reply other threads:[~2024-04-30 17:34 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.ea761e8c87cc41550b01d6fbc1cd1116af55e288.1714498385.git-series.marmarek@invisiblethingslab.com>
2024-04-30 17:33 ` Marek Marczykowski-Górecki [this message]
2024-04-30 17:33 ` [PATCH v2 2/3] Update Xen's features.h header Marek Marczykowski-Górecki
2024-04-30 17:33 ` [PATCH v2 3/3] Do not access /dev/mem in MSI-X PCI passthrough on Xen Marek Marczykowski-Górecki
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3cc5a7d2e0338112fb87806c813627bdf5dbd2a5.1714498385.git-series.marmarek@invisiblethingslab.com \
--to=marmarek@invisiblethingslab.com \
--cc=anthony.perard@citrix.com \
--cc=paul@xen.org \
--cc=qemu-devel@nongnu.org \
--cc=sstabellini@kernel.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).