From 3a35ce7dcefe9e80a00603a195269fbaf6e7d901 Mon Sep 17 00:00:00 2001 From: Roel Kluin Date: Thu, 22 Jan 2009 16:42:57 +0100 Subject: virtio: fix BAD_RING, START_US and END_USE macros Impact: cleanup fix BAD_RING, START_US and END_USE macros When these macros aren't called with a variable named vq as first argument, this would result in a build failure. Signed-off-by: Roel Kluin Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 5777196bf6c..12273bf9b3b 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -23,15 +23,15 @@ #ifdef DEBUG /* For development, we want to crash whenever the ring is screwed. */ -#define BAD_RING(vq, fmt...) \ - do { dev_err(&vq->vq.vdev->dev, fmt); BUG(); } while(0) -#define START_USE(vq) \ - do { if ((vq)->in_use) panic("in_use = %i\n", (vq)->in_use); (vq)->in_use = __LINE__; mb(); } while(0) -#define END_USE(vq) \ - do { BUG_ON(!(vq)->in_use); (vq)->in_use = 0; mb(); } while(0) +#define BAD_RING(_vq, fmt...) \ + do { dev_err(&_vq->vq.vdev->dev, fmt); BUG(); } while(0) +#define START_USE(_vq) \ + do { if ((_vq)->in_use) panic("in_use = %i\n", (_vq)->in_use); (_vq)->in_use = __LINE__; mb(); } while(0) +#define END_USE(_vq) \ + do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; mb(); } while(0) #else -#define BAD_RING(vq, fmt...) \ - do { dev_err(&vq->vq.vdev->dev, fmt); (vq)->broken = true; } while(0) +#define BAD_RING(_vq, fmt...) \ + do { dev_err(&_vq->vq.vdev->dev, fmt); (_vq)->broken = true; } while(0) #define START_USE(vq) #define END_USE(vq) #endif -- cgit v1.2.3 From c5f841f1780dad7efb7eca092f60742d47f47d25 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 30 Mar 2009 21:55:22 -0600 Subject: virtio: more neatening of virtio_ring macros. Impact: cleanup Roel Kluin drew attention to these macros with his patch: here I neaten them a little further: 1) Add a comment on what START_USE and END_USE are checking, 2) Brackets around _vq in BAD_RING, 3) Neaten formatting for START_USE so it's less than 80 cols. Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 12273bf9b3b..5c52369ab9b 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -24,9 +24,15 @@ #ifdef DEBUG /* For development, we want to crash whenever the ring is screwed. */ #define BAD_RING(_vq, fmt...) \ - do { dev_err(&_vq->vq.vdev->dev, fmt); BUG(); } while(0) -#define START_USE(_vq) \ - do { if ((_vq)->in_use) panic("in_use = %i\n", (_vq)->in_use); (_vq)->in_use = __LINE__; mb(); } while(0) + do { dev_err(&(_vq)->vq.vdev->dev, fmt); BUG(); } while(0) +/* Caller is supposed to guarantee no reentry. */ +#define START_USE(_vq) \ + do { \ + if ((_vq)->in_use) \ + panic("in_use = %i\n", (_vq)->in_use); \ + (_vq)->in_use = __LINE__; \ + mb(); \ + } while(0) #define END_USE(_vq) \ do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; mb(); } while(0) #else -- cgit v1.2.3 From 6afbdd059c27330eccbd85943354f94c2b83a7fe Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 30 Mar 2009 21:55:23 -0600 Subject: lguest: fix spurious BUG_ON() on invalid guest stack. Impact: fix crash on misbehaving guest gpte_addr() contains a BUG_ON(), insisting that the present flag is set. We need to return before we call it if that isn't the case. Signed-off-by: Rusty Russell Cc: stable@kernel.org --- drivers/lguest/page_tables.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c index 576a8318221..82ff484bd8c 100644 --- a/drivers/lguest/page_tables.c +++ b/drivers/lguest/page_tables.c @@ -373,8 +373,10 @@ unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr) /* First step: get the top-level Guest page table entry. */ gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t); /* Toplevel not present? We can't map it in. */ - if (!(pgd_flags(gpgd) & _PAGE_PRESENT)) + if (!(pgd_flags(gpgd) & _PAGE_PRESENT)) { kill_guest(cpu, "Bad address %#lx", vaddr); + return -1UL; + } gpte = lgread(cpu, gpte_addr(gpgd, vaddr), pte_t); if (!(pte_flags(gpte) & _PAGE_PRESENT)) -- cgit v1.2.3 From b7ff99ea53cd16de8f6166c0e98f19a7c6ca67ee Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 30 Mar 2009 21:55:23 -0600 Subject: lguest: wire up pte_update/pte_update_defer Impact: intermittent guest segv/crash fix I've been seeing random guest bad address crashes and segmentation faults: bisect led to 4f98a2fee8 (vmscan: split LRU lists into anon & file sets), but that's a red herring. It turns out that lguest never hooked up the pte_update/pte_update_defer calls, so our ptes were not always in sync. After the vmscan commit, the bug became reproducible; now a fsck in a 64MB guest causes reproducible pagetable corruption. Signed-off-by: Rusty Russell Cc: jeremy@xensource.com Cc: virtualization@lists.osdl.org Cc: stable@kernel.org --- arch/x86/lguest/boot.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 9fe4ddaa8f6..7822d29b02c 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -490,11 +490,17 @@ static void lguest_write_cr4(unsigned long val) * into a process' address space. We set the entry then tell the Host the * toplevel and address this corresponds to. The Guest uses one pagetable per * process, so we need to tell the Host which one we're changing (mm->pgd). */ +static void lguest_pte_update(struct mm_struct *mm, unsigned long addr, + pte_t *ptep) +{ + lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low); +} + static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pteval) { *ptep = pteval; - lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, pteval.pte_low); + lguest_pte_update(mm, addr, ptep); } /* The Guest calls this to set a top-level entry. Again, we set the entry then @@ -1040,6 +1046,8 @@ __init void lguest_init(void) pv_mmu_ops.read_cr3 = lguest_read_cr3; pv_mmu_ops.lazy_mode.enter = paravirt_enter_lazy_mmu; pv_mmu_ops.lazy_mode.leave = lguest_leave_lazy_mode; + pv_mmu_ops.pte_update = lguest_pte_update; + pv_mmu_ops.pte_update_defer = lguest_pte_update; #ifdef CONFIG_X86_LOCAL_APIC /* apic read/write intercepts */ -- cgit v1.2.3 From 4cd8b5e2a159f18a1507f1187b44a1acbfa6341b Mon Sep 17 00:00:00 2001 From: Matias Zabaljauregui Date: Sat, 14 Mar 2009 13:37:52 -0200 Subject: lguest: use KVM hypercalls Impact: cleanup This patch allow us to use KVM hypercalls Signed-off-by: Matias Zabaljauregui Signed-off-by: Rusty Russell --- arch/x86/include/asm/lguest_hcall.h | 24 ++--------- arch/x86/lguest/boot.c | 78 ++++++++++++++++++++++------------- arch/x86/lguest/i386_head.S | 4 +- drivers/lguest/interrupts_and_traps.c | 7 ++-- drivers/lguest/lguest_device.c | 4 +- drivers/lguest/x86/core.c | 62 +++++++++++++++++++++++++++- 6 files changed, 122 insertions(+), 57 deletions(-) diff --git a/arch/x86/include/asm/lguest_hcall.h b/arch/x86/include/asm/lguest_hcall.h index 43894428c3c..0f4ee7148af 100644 --- a/arch/x86/include/asm/lguest_hcall.h +++ b/arch/x86/include/asm/lguest_hcall.h @@ -26,36 +26,20 @@ #ifndef __ASSEMBLY__ #include +#include /*G:031 But first, how does our Guest contact the Host to ask for privileged * operations? There are two ways: the direct way is to make a "hypercall", * to make requests of the Host Itself. * - * Our hypercall mechanism uses the highest unused trap code (traps 32 and - * above are used by real hardware interrupts). Fifteen hypercalls are + * We use the KVM hypercall mechanism. Eighteen hypercalls are * available: the hypercall number is put in the %eax register, and the - * arguments (when required) are placed in %edx, %ebx and %ecx. If a return + * arguments (when required) are placed in %ebx, %ecx and %edx. If a return * value makes sense, it's returned in %eax. * * Grossly invalid calls result in Sudden Death at the hands of the vengeful * Host, rather than returning failure. This reflects Winston Churchill's * definition of a gentleman: "someone who is only rude intentionally". */ -static inline unsigned long -hcall(unsigned long call, - unsigned long arg1, unsigned long arg2, unsigned long arg3) -{ - /* "int" is the Intel instruction to trigger a trap. */ - asm volatile("int $" __stringify(LGUEST_TRAP_ENTRY) - /* The call in %eax (aka "a") might be overwritten */ - : "=a"(call) - /* The arguments are in %eax, %edx, %ebx & %ecx */ - : "a"(call), "d"(arg1), "b"(arg2), "c"(arg3) - /* "memory" means this might write somewhere in memory. - * This isn't true for all calls, but it's safe to tell - * gcc that it might happen so it doesn't get clever. */ - : "memory"); - return call; -} /*:*/ /* Can't use our min() macro here: needs to be a constant */ @@ -64,7 +48,7 @@ hcall(unsigned long call, #define LHCALL_RING_SIZE 64 struct hcall_args { /* These map directly onto eax, ebx, ecx, edx in struct lguest_regs */ - unsigned long arg0, arg2, arg3, arg1; + unsigned long arg0, arg1, arg2, arg3; }; #endif /* !__ASSEMBLY__ */ diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 7822d29b02c..5be9293961b 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -107,7 +107,7 @@ static void async_hcall(unsigned long call, unsigned long arg1, local_irq_save(flags); if (lguest_data.hcall_status[next_call] != 0xFF) { /* Table full, so do normal hcall which will flush table. */ - hcall(call, arg1, arg2, arg3); + kvm_hypercall3(call, arg1, arg2, arg3); } else { lguest_data.hcalls[next_call].arg0 = call; lguest_data.hcalls[next_call].arg1 = arg1; @@ -134,13 +134,32 @@ static void async_hcall(unsigned long call, unsigned long arg1, * * So, when we're in lazy mode, we call async_hcall() to store the call for * future processing: */ -static void lazy_hcall(unsigned long call, +static void lazy_hcall1(unsigned long call, + unsigned long arg1) +{ + if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) + kvm_hypercall1(call, arg1); + else + async_hcall(call, arg1, 0, 0); +} + +static void lazy_hcall2(unsigned long call, + unsigned long arg1, + unsigned long arg2) +{ + if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) + kvm_hypercall2(call, arg1, arg2); + else + async_hcall(call, arg1, arg2, 0); +} + +static void lazy_hcall3(unsigned long call, unsigned long arg1, unsigned long arg2, unsigned long arg3) { if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) - hcall(call, arg1, arg2, arg3); + kvm_hypercall3(call, arg1, arg2, arg3); else async_hcall(call, arg1, arg2, arg3); } @@ -150,7 +169,7 @@ static void lazy_hcall(unsigned long call, static void lguest_leave_lazy_mode(void) { paravirt_leave_lazy(paravirt_get_lazy_mode()); - hcall(LHCALL_FLUSH_ASYNC, 0, 0, 0); + kvm_hypercall0(LHCALL_FLUSH_ASYNC); } /*G:033 @@ -229,7 +248,7 @@ static void lguest_write_idt_entry(gate_desc *dt, /* Keep the local copy up to date. */ native_write_idt_entry(dt, entrynum, g); /* Tell Host about this new entry. */ - hcall(LHCALL_LOAD_IDT_ENTRY, entrynum, desc[0], desc[1]); + kvm_hypercall3(LHCALL_LOAD_IDT_ENTRY, entrynum, desc[0], desc[1]); } /* Changing to a different IDT is very rare: we keep the IDT up-to-date every @@ -241,7 +260,7 @@ static void lguest_load_idt(const struct desc_ptr *desc) struct desc_struct *idt = (void *)desc->address; for (i = 0; i < (desc->size+1)/8; i++) - hcall(LHCALL_LOAD_IDT_ENTRY, i, idt[i].a, idt[i].b); + kvm_hypercall3(LHCALL_LOAD_IDT_ENTRY, i, idt[i].a, idt[i].b); } /* @@ -261,8 +280,8 @@ static void lguest_load_idt(const struct desc_ptr *desc) */ static void lguest_load_gdt(const struct desc_ptr *desc) { - BUG_ON((desc->size+1)/8 != GDT_ENTRIES); - hcall(LHCALL_LOAD_GDT, __pa(desc->address), GDT_ENTRIES, 0); + BUG_ON((desc->size + 1) / 8 != GDT_ENTRIES); + kvm_hypercall2(LHCALL_LOAD_GDT, __pa(desc->address), GDT_ENTRIES); } /* For a single GDT entry which changes, we do the lazy thing: alter our GDT, @@ -272,7 +291,7 @@ static void lguest_write_gdt_entry(struct desc_struct *dt, int entrynum, const void *desc, int type) { native_write_gdt_entry(dt, entrynum, desc, type); - hcall(LHCALL_LOAD_GDT, __pa(dt), GDT_ENTRIES, 0); + kvm_hypercall2(LHCALL_LOAD_GDT, __pa(dt), GDT_ENTRIES); } /* OK, I lied. There are three "thread local storage" GDT entries which change @@ -284,7 +303,7 @@ static void lguest_load_tls(struct thread_struct *t, unsigned int cpu) * can't handle us removing entries we're currently using. So we clear * the GS register here: if it's needed it'll be reloaded anyway. */ lazy_load_gs(0); - lazy_hcall(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu, 0); + lazy_hcall2(LHCALL_LOAD_TLS, __pa(&t->tls_array), cpu); } /*G:038 That's enough excitement for now, back to ploughing through each of @@ -382,7 +401,7 @@ static void lguest_cpuid(unsigned int *ax, unsigned int *bx, static unsigned long current_cr0; static void lguest_write_cr0(unsigned long val) { - lazy_hcall(LHCALL_TS, val & X86_CR0_TS, 0, 0); + lazy_hcall1(LHCALL_TS, val & X86_CR0_TS); current_cr0 = val; } @@ -396,7 +415,7 @@ static unsigned long lguest_read_cr0(void) * the vowels have been optimized out. */ static void lguest_clts(void) { - lazy_hcall(LHCALL_TS, 0, 0, 0); + lazy_hcall1(LHCALL_TS, 0); current_cr0 &= ~X86_CR0_TS; } @@ -418,7 +437,7 @@ static bool cr3_changed = false; static void lguest_write_cr3(unsigned long cr3) { lguest_data.pgdir = cr3; - lazy_hcall(LHCALL_NEW_PGTABLE, cr3, 0, 0); + lazy_hcall1(LHCALL_NEW_PGTABLE, cr3); cr3_changed = true; } @@ -493,7 +512,7 @@ static void lguest_write_cr4(unsigned long val) static void lguest_pte_update(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { - lazy_hcall(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low); + lazy_hcall3(LHCALL_SET_PTE, __pa(mm->pgd), addr, ptep->pte_low); } static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr, @@ -509,8 +528,8 @@ static void lguest_set_pte_at(struct mm_struct *mm, unsigned long addr, static void lguest_set_pmd(pmd_t *pmdp, pmd_t pmdval) { *pmdp = pmdval; - lazy_hcall(LHCALL_SET_PMD, __pa(pmdp)&PAGE_MASK, - (__pa(pmdp)&(PAGE_SIZE-1))/4, 0); + lazy_hcall2(LHCALL_SET_PMD, __pa(pmdp) & PAGE_MASK, + (__pa(pmdp) & (PAGE_SIZE - 1)) / 4); } /* There are a couple of legacy places where the kernel sets a PTE, but we @@ -526,7 +545,7 @@ static void lguest_set_pte(pte_t *ptep, pte_t pteval) { *ptep = pteval; if (cr3_changed) - lazy_hcall(LHCALL_FLUSH_TLB, 1, 0, 0); + lazy_hcall1(LHCALL_FLUSH_TLB, 1); } /* Unfortunately for Lguest, the pv_mmu_ops for page tables were based on @@ -542,7 +561,7 @@ static void lguest_set_pte(pte_t *ptep, pte_t pteval) static void lguest_flush_tlb_single(unsigned long addr) { /* Simply set it to zero: if it was not, it will fault back in. */ - lazy_hcall(LHCALL_SET_PTE, lguest_data.pgdir, addr, 0); + lazy_hcall3(LHCALL_SET_PTE, lguest_data.pgdir, addr, 0); } /* This is what happens after the Guest has removed a large number of entries. @@ -550,7 +569,7 @@ static void lguest_flush_tlb_single(unsigned long addr) * have changed, ie. virtual addresses below PAGE_OFFSET. */ static void lguest_flush_tlb_user(void) { - lazy_hcall(LHCALL_FLUSH_TLB, 0, 0, 0); + lazy_hcall1(LHCALL_FLUSH_TLB, 0); } /* This is called when the kernel page tables have changed. That's not very @@ -558,7 +577,7 @@ static void lguest_flush_tlb_user(void) * slow), so it's worth separating this from the user flushing above. */ static void lguest_flush_tlb_kernel(void) { - lazy_hcall(LHCALL_FLUSH_TLB, 1, 0, 0); + lazy_hcall1(LHCALL_FLUSH_TLB, 1); } /* @@ -695,7 +714,7 @@ static int lguest_clockevent_set_next_event(unsigned long delta, } /* Please wake us this far in the future. */ - hcall(LHCALL_SET_CLOCKEVENT, delta, 0, 0); + kvm_hypercall1(LHCALL_SET_CLOCKEVENT, delta); return 0; } @@ -706,7 +725,7 @@ static void lguest_clockevent_set_mode(enum clock_event_mode mode, case CLOCK_EVT_MODE_UNUSED: case CLOCK_EVT_MODE_SHUTDOWN: /* A 0 argument shuts the clock down. */ - hcall(LHCALL_SET_CLOCKEVENT, 0, 0, 0); + kvm_hypercall0(LHCALL_SET_CLOCKEVENT); break; case CLOCK_EVT_MODE_ONESHOT: /* This is what we expect. */ @@ -781,8 +800,8 @@ static void lguest_time_init(void) static void lguest_load_sp0(struct tss_struct *tss, struct thread_struct *thread) { - lazy_hcall(LHCALL_SET_STACK, __KERNEL_DS|0x1, thread->sp0, - THREAD_SIZE/PAGE_SIZE); + lazy_hcall3(LHCALL_SET_STACK, __KERNEL_DS | 0x1, thread->sp0, + THREAD_SIZE / PAGE_SIZE); } /* Let's just say, I wouldn't do debugging under a Guest. */ @@ -855,7 +874,7 @@ static void set_lguest_basic_apic_ops(void) /* STOP! Until an interrupt comes in. */ static void lguest_safe_halt(void) { - hcall(LHCALL_HALT, 0, 0, 0); + kvm_hypercall0(LHCALL_HALT); } /* The SHUTDOWN hypercall takes a string to describe what's happening, and @@ -865,7 +884,8 @@ static void lguest_safe_halt(void) * rather than virtual addresses, so we use __pa() here. */ static void lguest_power_off(void) { - hcall(LHCALL_SHUTDOWN, __pa("Power down"), LGUEST_SHUTDOWN_POWEROFF, 0); + kvm_hypercall2(LHCALL_SHUTDOWN, __pa("Power down"), + LGUEST_SHUTDOWN_POWEROFF); } /* @@ -875,7 +895,7 @@ static void lguest_power_off(void) */ static int lguest_panic(struct notifier_block *nb, unsigned long l, void *p) { - hcall(LHCALL_SHUTDOWN, __pa(p), LGUEST_SHUTDOWN_POWEROFF, 0); + kvm_hypercall2(LHCALL_SHUTDOWN, __pa(p), LGUEST_SHUTDOWN_POWEROFF); /* The hcall won't return, but to keep gcc happy, we're "done". */ return NOTIFY_DONE; } @@ -916,7 +936,7 @@ static __init int early_put_chars(u32 vtermno, const char *buf, int count) len = sizeof(scratch) - 1; scratch[len] = '\0'; memcpy(scratch, buf, len); - hcall(LHCALL_NOTIFY, __pa(scratch), 0, 0); + kvm_hypercall1(LHCALL_NOTIFY, __pa(scratch)); /* This routine returns the number of bytes actually written. */ return len; @@ -926,7 +946,7 @@ static __init int early_put_chars(u32 vtermno, const char *buf, int count) * Launcher to reboot us. */ static void lguest_restart(char *reason) { - hcall(LHCALL_SHUTDOWN, __pa(reason), LGUEST_SHUTDOWN_RESTART, 0); + kvm_hypercall2(LHCALL_SHUTDOWN, __pa(reason), LGUEST_SHUTDOWN_RESTART); } /*G:050 diff --git a/arch/x86/lguest/i386_head.S b/arch/x86/lguest/i386_head.S index 10b9bd35a8f..f7954198947 100644 --- a/arch/x86/lguest/i386_head.S +++ b/arch/x86/lguest/i386_head.S @@ -27,8 +27,8 @@ ENTRY(lguest_entry) /* We make the "initialization" hypercall now to tell the Host about * us, and also find out where it put our page tables. */ movl $LHCALL_LGUEST_INIT, %eax - movl $lguest_data - __PAGE_OFFSET, %edx - int $LGUEST_TRAP_ENTRY + movl $lguest_data - __PAGE_OFFSET, %ebx + .byte 0x0f,0x01,0xc1 /* KVM_HYPERCALL */ /* Set up the initial stack so we can run C code. */ movl $(init_thread_union+THREAD_SIZE),%esp diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c index 415fab0125a..504091da173 100644 --- a/drivers/lguest/interrupts_and_traps.c +++ b/drivers/lguest/interrupts_and_traps.c @@ -288,9 +288,10 @@ static int direct_trap(unsigned int num) /* The Host needs to see page faults (for shadow paging and to save the * fault address), general protection faults (in/out emulation) and - * device not available (TS handling), and of course, the hypercall - * trap. */ - return num != 14 && num != 13 && num != 7 && num != LGUEST_TRAP_ENTRY; + * device not available (TS handling), invalid opcode fault (kvm hcall), + * and of course, the hypercall trap. */ + return num != 14 && num != 13 && num != 7 && + num != 6 && num != LGUEST_TRAP_ENTRY; } /*:*/ diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c index 8132533d71f..df44d962626 100644 --- a/drivers/lguest/lguest_device.c +++ b/drivers/lguest/lguest_device.c @@ -161,7 +161,7 @@ static void set_status(struct virtio_device *vdev, u8 status) /* We set the status. */ to_lgdev(vdev)->desc->status = status; - hcall(LHCALL_NOTIFY, (max_pfn<priv; - hcall(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT, 0, 0); + kvm_hypercall1(LHCALL_NOTIFY, lvq->config.pfn << PAGE_SHIFT); } /* An extern declaration inside a C file is bad form. Don't do it. */ diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c index bf7942327bd..a6b717644be 100644 --- a/drivers/lguest/x86/core.c +++ b/drivers/lguest/x86/core.c @@ -290,6 +290,57 @@ static int emulate_insn(struct lg_cpu *cpu) return 1; } +/* Our hypercalls mechanism used to be based on direct software interrupts. + * After Anthony's "Refactor hypercall infrastructure" kvm patch, we decided to + * change over to using kvm hypercalls. + * + * KVM_HYPERCALL is actually a "vmcall" instruction, which generates an invalid + * opcode fault (fault 6) on non-VT cpus, so the easiest solution seemed to be + * an *emulation approach*: if the fault was really produced by an hypercall + * (is_hypercall() does exactly this check), we can just call the corresponding + * hypercall host implementation function. + * + * But these invalid opcode faults are notably slower than software interrupts. + * So we implemented the *patching (or rewriting) approach*: every time we hit + * the KVM_HYPERCALL opcode in Guest code, we patch it to the old "int 0x1f" + * opcode, so next time the Guest calls this hypercall it will use the + * faster trap mechanism. + * + * Matias even benchmarked it to convince you: this shows the average cycle + * cost of a hypercall. For each alternative solution mentioned above we've + * made 5 runs of the benchmark: + * + * 1) direct software interrupt: 2915, 2789, 2764, 2721, 2898 + * 2) emulation technique: 3410, 3681, 3466, 3392, 3780 + * 3) patching (rewrite) technique: 2977, 2975, 2891, 2637, 2884 + * + * One two-line function is worth a 20% hypercall speed boost! + */ +static void rewrite_hypercall(struct lg_cpu *cpu) +{ + /* This are the opcodes we use to patch the Guest. The opcode for "int + * $0x1f" is "0xcd 0x1f" but vmcall instruction is 3 bytes long, so we + * complete the sequence with a NOP (0x90). */ + u8 insn[3] = {0xcd, 0x1f, 0x90}; + + __lgwrite(cpu, guest_pa(cpu, cpu->regs->eip), insn, sizeof(insn)); +} + +static bool is_hypercall(struct lg_cpu *cpu) +{ + u8 insn[3]; + + /* This must be the Guest kernel trying to do something. + * The bottom two bits of the CS segment register are the privilege + * level. */ + if ((cpu->regs->cs & 3) != GUEST_PL) + return false; + + /* Is it a vmcall? */ + __lgread(cpu, insn, guest_pa(cpu, cpu->regs->eip), sizeof(insn)); + return insn[0] == 0x0f && insn[1] == 0x01 && insn[2] == 0xc1; +} + /*H:050 Once we've re-enabled interrupts, we look at why the Guest exited. */ void lguest_arch_handle_trap(struct lg_cpu *cpu) { @@ -337,7 +388,7 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu) break; case 32 ... 255: /* These values mean a real interrupt occurred, in which case - * the Host handler has already been run. We just do a + * the Host handler has already been run. We just do a * friendly check if another process should now be run, then * return to run the Guest again */ cond_resched(); @@ -347,6 +398,15 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu) * up the pointer now to indicate a hypercall is pending. */ cpu->hcall = (struct hcall_args *)cpu->regs; return; + case 6: + /* kvm hypercalls trigger an invalid opcode fault (6). + * We need to check if ring == GUEST_PL and + * faulting instruction == vmcall. */ + if (is_hypercall(cpu)) { + rewrite_hypercall(cpu); + return; + } + break; } /* We didn't handle the trap, so it needs to go to the Guest. */ -- cgit v1.2.3 From df1693abc42e34bbc4351e179dbe66c28a94efb8 Mon Sep 17 00:00:00 2001 From: Matias Zabaljauregui Date: Wed, 18 Mar 2009 13:38:35 -0300 Subject: lguest: use bool instead of int Impact: clean up Rusty told me, some time ago, that he had become a fan of "bool". So, here are some replacements. Signed-off-by: Matias Zabaljauregui Signed-off-by: Rusty Russell --- drivers/lguest/core.c | 4 ++-- drivers/lguest/interrupts_and_traps.c | 21 +++++++++++---------- drivers/lguest/lg.h | 8 ++++---- drivers/lguest/page_tables.c | 18 +++++++++--------- drivers/lguest/segments.c | 2 +- 5 files changed, 27 insertions(+), 26 deletions(-) diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c index 60156dfdc60..4845fb3cf74 100644 --- a/drivers/lguest/core.c +++ b/drivers/lguest/core.c @@ -152,8 +152,8 @@ static void unmap_switcher(void) * code. We have to check that the range is below the pfn_limit the Launcher * gave us. We have to make sure that addr + len doesn't give us a false * positive by overflowing, too. */ -int lguest_address_ok(const struct lguest *lg, - unsigned long addr, unsigned long len) +bool lguest_address_ok(const struct lguest *lg, + unsigned long addr, unsigned long len) { return (addr+len) / PAGE_SIZE < lg->pfn_limit && (addr+len >= addr); } diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c index 504091da173..6e99adbe194 100644 --- a/drivers/lguest/interrupts_and_traps.c +++ b/drivers/lguest/interrupts_and_traps.c @@ -34,7 +34,7 @@ static int idt_type(u32 lo, u32 hi) } /* An IDT entry can't be used unless the "present" bit is set. */ -static int idt_present(u32 lo, u32 hi) +static bool idt_present(u32 lo, u32 hi) { return (hi & 0x8000); } @@ -60,7 +60,8 @@ static void push_guest_stack(struct lg_cpu *cpu, unsigned long *gstack, u32 val) * We set up the stack just like the CPU does for a real interrupt, so it's * identical for the Guest (and the standard "iret" instruction will undo * it). */ -static void set_guest_interrupt(struct lg_cpu *cpu, u32 lo, u32 hi, int has_err) +static void set_guest_interrupt(struct lg_cpu *cpu, u32 lo, u32 hi, + bool has_err) { unsigned long gstack, origstack; u32 eflags, ss, irq_enable; @@ -184,7 +185,7 @@ void maybe_do_interrupt(struct lg_cpu *cpu) /* set_guest_interrupt() takes the interrupt descriptor and a * flag to say whether this interrupt pushes an error code onto * the stack as well: virtual interrupts never do. */ - set_guest_interrupt(cpu, idt->a, idt->b, 0); + set_guest_interrupt(cpu, idt->a, idt->b, false); } /* Every time we deliver an interrupt, we update the timestamp in the @@ -244,26 +245,26 @@ void free_interrupts(void) /*H:220 Now we've got the routines to deliver interrupts, delivering traps like * page fault is easy. The only trick is that Intel decided that some traps * should have error codes: */ -static int has_err(unsigned int trap) +static bool has_err(unsigned int trap) { return (trap == 8 || (trap >= 10 && trap <= 14) || trap == 17); } /* deliver_trap() returns true if it could deliver the trap. */ -int deliver_trap(struct lg_cpu *cpu, unsigned int num) +bool deliver_trap(struct lg_cpu *cpu, unsigned int num) { /* Trap numbers are always 8 bit, but we set an impossible trap number * for traps inside the Switcher, so check that here. */ if (num >= ARRAY_SIZE(cpu->arch.idt)) - return 0; + return false; /* Early on the Guest hasn't set the IDT entries (or maybe it put a * bogus one in): if we fail here, the Guest will be killed. */ if (!idt_present(cpu->arch.idt[num].a, cpu->arch.idt[num].b)) - return 0; + return false; set_guest_interrupt(cpu, cpu->arch.idt[num].a, cpu->arch.idt[num].b, has_err(num)); - return 1; + return true; } /*H:250 Here's the hard part: returning to the Host every time a trap happens @@ -279,12 +280,12 @@ int deliver_trap(struct lg_cpu *cpu, unsigned int num) * * This routine indicates if a particular trap number could be delivered * directly. */ -static int direct_trap(unsigned int num) +static bool direct_trap(unsigned int num) { /* Hardware interrupts don't go to the Guest at all (except system * call). */ if (num >= FIRST_EXTERNAL_VECTOR && !could_be_syscall(num)) - return 0; + return false; /* The Host needs to see page faults (for shadow paging and to save the * fault address), general protection faults (in/out emulation) and diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h index f2c641e0bdd..ac8a4a3741b 100644 --- a/drivers/lguest/lg.h +++ b/drivers/lguest/lg.h @@ -109,8 +109,8 @@ struct lguest extern struct mutex lguest_lock; /* core.c: */ -int lguest_address_ok(const struct lguest *lg, - unsigned long addr, unsigned long len); +bool lguest_address_ok(const struct lguest *lg, + unsigned long addr, unsigned long len); void __lgread(struct lg_cpu *, void *, unsigned long, unsigned); void __lgwrite(struct lg_cpu *, unsigned long, const void *, unsigned); @@ -140,7 +140,7 @@ int run_guest(struct lg_cpu *cpu, unsigned long __user *user); /* interrupts_and_traps.c: */ void maybe_do_interrupt(struct lg_cpu *cpu); -int deliver_trap(struct lg_cpu *cpu, unsigned int num); +bool deliver_trap(struct lg_cpu *cpu, unsigned int num); void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i, u32 low, u32 hi); void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages); @@ -173,7 +173,7 @@ void guest_pagetable_flush_user(struct lg_cpu *cpu); void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir, unsigned long vaddr, pte_t val); void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages); -int demand_page(struct lg_cpu *cpu, unsigned long cr2, int errcode); +bool demand_page(struct lg_cpu *cpu, unsigned long cr2, int errcode); void pin_page(struct lg_cpu *cpu, unsigned long vaddr); unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr); void page_table_guest_data_init(struct lg_cpu *cpu); diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c index 82ff484bd8c..a059cf9980f 100644 --- a/drivers/lguest/page_tables.c +++ b/drivers/lguest/page_tables.c @@ -199,7 +199,7 @@ static void check_gpgd(struct lg_cpu *cpu, pgd_t gpgd) * * If we fixed up the fault (ie. we mapped the address), this routine returns * true. Otherwise, it was a real fault and we need to tell the Guest. */ -int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) +bool demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) { pgd_t gpgd; pgd_t *spgd; @@ -211,7 +211,7 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) gpgd = lgread(cpu, gpgd_addr(cpu, vaddr), pgd_t); /* Toplevel not present? We can't map it in. */ if (!(pgd_flags(gpgd) & _PAGE_PRESENT)) - return 0; + return false; /* Now look at the matching shadow entry. */ spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr); @@ -222,7 +222,7 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) * simple for this corner case. */ if (!ptepage) { kill_guest(cpu, "out of memory allocating pte page"); - return 0; + return false; } /* We check that the Guest pgd is OK. */ check_gpgd(cpu, gpgd); @@ -238,16 +238,16 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) /* If this page isn't in the Guest page tables, we can't page it in. */ if (!(pte_flags(gpte) & _PAGE_PRESENT)) - return 0; + return false; /* Check they're not trying to write to a page the Guest wants * read-only (bit 2 of errcode == write). */ if ((errcode & 2) && !(pte_flags(gpte) & _PAGE_RW)) - return 0; + return false; /* User access to a kernel-only page? (bit 3 == user access) */ if ((errcode & 4) && !(pte_flags(gpte) & _PAGE_USER)) - return 0; + return false; /* Check that the Guest PTE flags are OK, and the page number is below * the pfn_limit (ie. not mapping the Launcher binary). */ @@ -283,7 +283,7 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) * manipulated, the result returned and the code complete. A small * delay and a trace of alliteration are the only indications the Guest * has that a page fault occurred at all. */ - return 1; + return true; } /*H:360 @@ -296,7 +296,7 @@ int demand_page(struct lg_cpu *cpu, unsigned long vaddr, int errcode) * * This is a quick version which answers the question: is this virtual address * mapped by the shadow page tables, and is it writable? */ -static int page_writable(struct lg_cpu *cpu, unsigned long vaddr) +static bool page_writable(struct lg_cpu *cpu, unsigned long vaddr) { pgd_t *spgd; unsigned long flags; @@ -304,7 +304,7 @@ static int page_writable(struct lg_cpu *cpu, unsigned long vaddr) /* Look at the current top level entry: is it present? */ spgd = spgd_addr(cpu, cpu->cpu_pgd, vaddr); if (!(pgd_flags(*spgd) & _PAGE_PRESENT)) - return 0; + return false; /* Check the flags on the pte entry itself: it must be present and * writable. */ diff --git a/drivers/lguest/segments.c b/drivers/lguest/segments.c index ec6aa3f1c36..4f15439b7f1 100644 --- a/drivers/lguest/segments.c +++ b/drivers/lguest/segments.c @@ -45,7 +45,7 @@ * "Task State Segment" which controls all kinds of delicate things. The * LGUEST_CS and LGUEST_DS entries are reserved for the Switcher, and the * the Guest can't be trusted to deal with double faults. */ -static int ignored_gdt(unsigned int num) +static bool ignored_gdt(unsigned int num) { return (num == GDT_ENTRY_TSS || num == GDT_ENTRY_LGUEST_CS -- cgit v1.2.3 From d1881d3192a3d3e8dc4f255b03187f4c36cb0617 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 30 Mar 2009 21:55:25 -0600 Subject: lguest: barrier me harder Impact: barrier correctness in example launcher I doubt either lguest user will complain about performance. Reported-by: Christoph Hellwig Cc: Jens Axboe Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index f2dbbf3bdea..d36fcc0f271 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -1630,6 +1630,13 @@ static bool service_io(struct device *dev) } } + /* OK, so we noted that it was pretty poor to use an fdatasync as a + * barrier. But Christoph Hellwig points out that we need a sync + * *afterwards* as well: "Barriers specify no reordering to the front + * or the back." And Jens Axboe confirmed it, so here we are: */ + if (out->type & VIRTIO_BLK_T_BARRIER) + fdatasync(vblk->fd); + /* We can't trigger an IRQ, because we're not the Launcher. It does * that when we tell it we're done. */ add_used(dev->vq, head, wlen); -- cgit v1.2.3