From 79f9ba78380fb3f4bf509e5c726c6cdd76e00c4f Mon Sep 17 00:00:00 2001 From: =?utf8?q?Roger=20Pau=20Monn=C3=A9?= Date: Tue, 17 Sep 2019 16:13:39 +0200 Subject: [PATCH] vpci: honor read-only devices MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Don't allow the hardware domain write access the PCI config space of devices marked as read-only. Signed-off-by: Roger Pau Monné Reviewed-by: Jan Beulich --- tools/tests/vpci/emul.h | 3 +++ xen/drivers/vpci/vpci.c | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/tools/tests/vpci/emul.h b/tools/tests/vpci/emul.h index 5d47544bf7..2e1d3057c9 100644 --- a/tools/tests/vpci/emul.h +++ b/tools/tests/vpci/emul.h @@ -92,6 +92,9 @@ typedef union { #define xfree(p) free(p) #define pci_get_pdev_by_domain(...) &test_pdev +#define pci_get_ro_map(...) NULL + +#define test_bit(...) false /* Dummy native helpers. Writes are ignored, reads return 1's. */ #define pci_conf_read8(...) 0xff diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c index 758d9420e7..cbd1bac7fc 100644 --- a/xen/drivers/vpci/vpci.c +++ b/xen/drivers/vpci/vpci.c @@ -411,6 +411,7 @@ void vpci_write(pci_sbdf_t sbdf, unsigned int reg, unsigned int size, const struct pci_dev *pdev; const struct vpci_register *r; unsigned int data_offset = 0; + const unsigned long *ro_map = pci_get_ro_map(sbdf.seg); if ( !size ) { @@ -418,6 +419,10 @@ void vpci_write(pci_sbdf_t sbdf, unsigned int reg, unsigned int size, return; } + if ( ro_map && test_bit(sbdf.bdf, ro_map) ) + /* Ignore writes to read-only devices. */ + return; + /* * Find the PCI dev matching the address. * Passthrough everything that's not trapped. -- 2.30.2