Hollis Blanchard wrote: > On Sat, 2008-02-16 at 17:09 -0500, Marcelo Tosatti wrote: > >> plain text document attachment (kvm-multicall) >> Batch pte updates and tlb flushes in lazy MMU mode. >> >> Signed-off-by: Marcelo Tosatti <[EMAIL PROTECTED]> >> Cc: Anthony Liguori <[EMAIL PROTECTED]> >> >> Index: kvm.paravirt/arch/x86/kernel/kvm.c >> =================================================================== >> --- kvm.paravirt.orig/arch/x86/kernel/kvm.c >> +++ kvm.paravirt/arch/x86/kernel/kvm.c >> @@ -25,6 +25,74 @@ >> #include <linux/kvm_para.h> >> #include <linux/cpu.h> >> #include <linux/mm.h> >> +#include <linux/hardirq.h> >> + >> +#define MAX_MULTICALL_NR (PAGE_SIZE / sizeof(struct kvm_multicall_entry)) >> + >> +struct kvm_para_state { >> + struct kvm_multicall_entry queue[MAX_MULTICALL_NR]; >> + int queue_index; >> + enum paravirt_lazy_mode mode; >> +}; >> + >> +static DEFINE_PER_CPU(struct kvm_para_state, para_state); >> > > AFAICS there is no guarantee about page-alignment here... > >
Right. >> +static int kvm_hypercall_multicall(struct kvm_vcpu *vcpu, gpa_t addr, u32 >> nents) >> +{ >> + int i, result = 0; >> + >> + ++vcpu->stat.multicall; >> + vcpu->stat.multicall_nr += nents; >> + >> + for (i = 0; i < nents; i++) { >> + struct kvm_multicall_entry mc; >> + int ret; >> + >> + down_read(&vcpu->kvm->slots_lock); >> + ret = kvm_read_guest(vcpu->kvm, addr, &mc, sizeof(mc)); >> + up_read(&vcpu->kvm->slots_lock); >> + if (ret) >> + return -KVM_EFAULT; >> + >> + ret = dispatch_hypercall(vcpu, mc.nr, mc.a0, mc.a1, mc.a2, >> + mc.a3); >> + if (ret) >> + result = ret; >> + addr += sizeof(mc); >> + } >> + if (result < 0) >> + return -KVM_EINVAL; >> + return result; >> +} >> > > ... but here you're assuming that 'queue' is physically contiguous, > which is not necessarily true one you cross a page boundary. > Kernel data is physically contiguous (true for per-cpu data as well?), so no there's issue here. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel