On Thu, Jan 24, 2013 at 05:04:32PM +0000, Christoffer Dall wrote: > On Thu, Jan 24, 2013 at 12:02 PM, Catalin Marinas > <catalin.marinas@xxxxxxx> wrote: > > On Thu, Jan 24, 2013 at 04:05:33PM +0000, Christoffer Dall wrote: > >> On Thu, Jan 24, 2013 at 6:39 AM, Catalin Marinas > >> <catalin.marinas@xxxxxxx> wrote: > >> > On Wed, Jan 16, 2013 at 05:57:26PM +0000, Christoffer Dall wrote: > >> >> @@ -82,6 +85,10 @@ extern pgprot_t pgprot_kernel; > >> >> #define PAGE_READONLY_EXEC _MOD_PROT(pgprot_user, L_PTE_USER | L_PTE_RDONLY) > >> >> #define PAGE_KERNEL _MOD_PROT(pgprot_kernel, L_PTE_XN) > >> >> #define PAGE_KERNEL_EXEC pgprot_kernel > >> >> +#define PAGE_HYP _MOD_PROT(pgprot_kernel, L_PTE_HYP) > >> >> +#define PAGE_HYP_DEVICE _MOD_PROT(pgprot_hyp_device, L_PTE_HYP) > >> >> +#define PAGE_S2 _MOD_PROT(pgprot_s2, L_PTE_S2_RDONLY) > >> >> +#define PAGE_S2_DEVICE _MOD_PROT(pgprot_s2_device, L_PTE_USER | L_PTE_S2_RDONLY) > >> > > >> > Are these S2 read-only by default? > >> > >> not sure I understand what you're asking here? > > > > Why do you pass L_PTE_S2_RDONLY? Do you need to restrict guest writes > > via the stage 2 attributes? > > > yes, for example when KSM merges two pages, then it must be mapped > read-only to the guest so that we catch writes and perform COW. OK, so you want the default to be read-only unless write access is required and you perform an 'or' with L_PTE_S2_RDWR. Sounds fine. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
