| Message ID | 1421179673-30754-1-git-send-email-julien.grall@linaro.org |
|---|---|
| State | Superseded, archived |
| Headers | show |
Hi Ian, On 14/01/15 11:02, Ian Campbell wrote: > On Tue, 2015-01-13 at 20:07 +0000, Julien Grall wrote: >> Some platform (such as the VFP Base AEMv8 model) has a memory mapped >> timer. We don't want DOM0 use this timer rather than the generic ARM >> timer. So blacklist it for all platforms. > > It seems that these registers contain things like the ability to stop > the counter or change its frequency. So we certainly don't want dom0 > getting at those! > > It's not clear to me if accesses to these registers are trapped > according to the controls available for the CP registers, or if we would > have to resort to trapping the entire MMIO page if we wanted to support > access to these registers (I don't think we would want to anyway). I didn't find any spec for the memory mapped timer. But looking to the driver, it looks like they also have the concept of physical/virtual. So we may not need to trap. Anyway, before implementing anything I'd like to find the corresponding spec. >> Signed-off-by: Julien Grall <julien.grall@linaro.org> >> >> --- >> This patch is candidate to backport for Xen 4.5 and Xen 4.4. >> >> It may not apply correctly for Xen 4.4. >> --- >> xen/arch/arm/domain_build.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c >> index bf8dc78..16ce248 100644 >> --- a/xen/arch/arm/domain_build.c >> +++ b/xen/arch/arm/domain_build.c >> @@ -1047,6 +1047,7 @@ static int handle_node(struct domain *d, struct kernel_info *kinfo, >> DT_MATCH_COMPATIBLE("arm,psci"), >> DT_MATCH_PATH("/cpus"), >> DT_MATCH_TYPE("memory"), >> + DT_MATCH_COMPATIBLE("arm,armv7-timer-mem"), > > This is a bit less obvious that the other things in this list. Could you > perhaps add a comment? Sure. I will send a new version. Regards,
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index bf8dc78..16ce248 100644 --- a/xen/arch/arm/domain_build.c +++ b/xen/arch/arm/domain_build.c @@ -1047,6 +1047,7 @@ static int handle_node(struct domain *d, struct kernel_info *kinfo, DT_MATCH_COMPATIBLE("arm,psci"), DT_MATCH_PATH("/cpus"), DT_MATCH_TYPE("memory"), + DT_MATCH_COMPATIBLE("arm,armv7-timer-mem"), { /* sentinel */ }, }; static const struct dt_device_match gic_matches[] __initconst =
Some platform (such as the VFP Base AEMv8 model) has a memory mapped timer. We don't want DOM0 use this timer rather than the generic ARM timer. So blacklist it for all platforms. Signed-off-by: Julien Grall <julien.grall@linaro.org> --- This patch is candidate to backport for Xen 4.5 and Xen 4.4. It may not apply correctly for Xen 4.4. --- xen/arch/arm/domain_build.c | 1 + 1 file changed, 1 insertion(+)