[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen/arm: dump guest stack even if not the current VCPU
Hi Frediano, Thank you for the patch. On 20/10/2014 16:39, Frediano Ziglio wrote: From: Frediano Ziglio <frediano.ziglio@xxxxxxxxxx> If show_guest_stack was called from Xen context (for instance hitting '0' key on Xen console) get_page_from_gva was not able to get the page returning NULL. Detecting different domain and changing VTTBR register make get_page_from_gva works for different domains. Signed-off-by: Frediano Ziglio <frediano.ziglio@xxxxxxxxxx> --- xen/arch/arm/p2m.c | 7 ++++++- xen/arch/arm/traps.c | 2 +- 2 files changed, 7 insertions(+), 2 deletions(-) Tested manually on a D01 board. I actually have only dom0 so EL1 is already pointing to the right domain. I have some doubt about the is_idle_domain test inside p2m_load_VTTBR. I guess this patch could be consider as a bug fix for Xen 4.5. It makes dump stack working when the dump domain key is hit. I used the "unlikely" to avoid decreasing performances on the normal cases, I'm fine if you remove them. I'm fine with keeping the unlikely. diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c index 1585d35..cf872fc 100644 --- a/xen/arch/arm/p2m.c +++ b/xen/arch/arm/p2m.c @@ -1178,7 +1178,8 @@ struct page_info *get_page_from_gva(struct domain *d, vaddr_t va, struct page_info *page = NULL; paddr_t maddr; - ASSERT(d == current->domain); + if ( unlikely(d != current->domain) ) + p2m_load_VTTBR(d); The code between the 2 p2m_load_VTTBR should not interrupted by an interrupt. I send a similar patch (https://patches.linaro.org/38895/) for flush_tlb_domain. spin_lock(&p2m->lock); I think taking the lock for the whole function is a bit too much here. IHMO, the lock is only necessary for gvirt_to_maddr. But this is 4.6 material if the patch reaches 4.5. Regards, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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