[PATCH 11/16] make registers per-vcpu

Glauber de Oliveira Costa
2008-01-07T13:10:18Z

This is the most obvious per-vcpu field: registers.

So this patch moves it from struct lguest to struct vcpu,
and patch the places in which they are used, accordingly

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
---
drivers/lguest/interrupts_and_traps.c | 29 ++++++++++++-----------
drivers/lguest/lg.h | 9 ++++---
drivers/lguest/lguest_user.c | 36 +++++++++++++++---------------
drivers/lguest/page_tables.c | 4 ++-
drivers/lguest/x86/core.c | 39 +++++++++++++++++----------------
5 files changed, 61 insertions(+), 56 deletions(-)

diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c
index d28671b..4cc7404 100644
--- a/drivers/lguest/interrupts_and_traps.c
+++ b/drivers/lguest/interrupts_and_traps.c
@@ -71,7 +71,7 @@ static void set_guest_interrupt(struct lg_vcpu *vcpu, u32 lo, u32 hi,
/* There are two cases for interrupts: one where the Guest is already
* in the kernel, and a more complex one where the Guest is in
* userspace. We check the privilege level to find out. */
- if ((lg->regs->ss&0x3) != GUEST_PL) {
+ if ((vcpu->regs->ss&0x3) != GUEST_PL) {
/* The Guest told us their kernel stack with the SET_STACK
* hypercall: both the virtual address and the segment */
virtstack = lg->esp1;
@@ -82,12 +82,12 @@ static void set_guest_interrupt(struct lg_vcpu *vcpu, u32 lo, u32 hi,
* stack: when the Guest does an "iret" back from the interrupt
* handler the CPU will notice they're dropping privilege
* levels and expect these here. */
- push_guest_stack(lg, &gstack, lg->regs->ss);
- push_guest_stack(lg, &gstack, lg->regs->esp);
+ push_guest_stack(lg, &gstack, vcpu->regs->ss);
+ push_guest_stack(lg, &gstack, vcpu->regs->esp);
} else {
/* We're staying on the same Guest (kernel) stack. */
- virtstack = lg->regs->esp;
- ss = lg->regs->ss;
+ virtstack = vcpu->regs->esp;
+ ss = vcpu->regs->ss;

origstack = gstack = guest_pa(lg, virtstack);
}
@@ -96,7 +96,7 @@ static void set_guest_interrupt(struct lg_vcpu *vcpu, u32 lo, u32 hi,
* the "Interrupt Flag" bit is always set. We copy that bit from the
* Guest's "irq_enabled" field into the eflags word: we saw the Guest
* copy it back in "lguest_iret". */
- eflags = lg->regs->eflags;
+ eflags = vcpu->regs->eflags;
if (get_user(irq_enable, &lg->lguest_data->irq_enabled) == 0
&& !(irq_enable & X86_EFLAGS_IF))
eflags &= ~X86_EFLAGS_IF;
@@ -105,19 +105,19 @@ static void set_guest_interrupt(struct lg_vcpu *vcpu, u32 lo, u32 hi,
* "eflags" word, the old code segment, and the old instruction
* pointer. */
push_guest_stack(lg, &gstack, eflags);
- push_guest_stack(lg, &gstack, lg->regs->cs);
- push_guest_stack(lg, &gstack, lg->regs->eip);
+ push_guest_stack(lg, &gstack, vcpu->regs->cs);
+ push_guest_stack(lg, &gstack, vcpu->regs->eip);

/* For the six traps which supply an error code, we push that, too. */
if (has_err)
- push_guest_stack(lg, &gstack, lg->regs->errcode);
+ push_guest_stack(lg, &gstack, vcpu->regs->errcode);

/* Now we've pushed all the old state, we change the stack, the code
* segment and the address to execute. */
- lg->regs->ss = ss;
- lg->regs->esp = virtstack + (gstack - origstack);
- lg->regs->cs = (__KERNEL_CS|GUEST_PL);
- lg->regs->eip = idt_address(lo, hi);
+ vcpu->regs->ss = ss;
+ vcpu->regs->esp = virtstack + (gstack - origstack);
+ vcpu->regs->cs = (__KERNEL_CS|GUEST_PL);
+ vcpu->regs->eip = idt_address(lo, hi);

/* There are two kinds of interrupt handlers: 0xE is an "interrupt
* gate" which expects interrupts to be disabled on entry. */
@@ -158,7 +158,8 @@ void maybe_do_interrupt(struct lg_vcpu *vcpu)

/* They may be in the middle of an iret, where they asked us never to
* deliver interrupts. */
- if (lg->regs->eip >= lg->noirq_start && lg->regs->eip < lg->noirq_end)
+ if ((vcpu->regs->eip >= lg->noirq_start) &&
+ (vcpu->regs->eip < lg->noirq_end))
return;

/* If they're halted, interrupts restart them. */
diff --git a/drivers/lguest/lg.h b/drivers/lguest/lg.h
index f871737..d8429a0 100644
--- a/drivers/lguest/lg.h
+++ b/drivers/lguest/lg.h
@@ -44,6 +44,10 @@ struct lg_vcpu {
int vcpu_id;
struct lguest *lg;

+ /* At end of a page shared mapped over lguest_pages in guest. */
+ unsigned long regs_page;
+ struct lguest_regs *regs;
+
/* If a hypercall was asked for, this points to the arguments. */
struct hcall_args *hcall;
u32 next_hcall;
@@ -58,9 +62,6 @@ struct lg_vcpu {
/* The private info the thread maintains about the guest. */
struct lguest
{
- /* At end of a page shared mapped over lguest_pages in guest. */
- unsigned long regs_page;
- struct lguest_regs *regs;
struct lguest_data __user *lguest_data;
struct task_struct *tsk;
struct mm_struct *mm; /* == tsk->mm, but that becomes NULL on exit */
@@ -182,7 +183,7 @@ void lguest_arch_run_guest(struct lg_vcpu *vcpu);
void lguest_arch_handle_trap(struct lg_vcpu *vcpu);
int lguest_arch_init_hypercalls(struct lg_vcpu *vcpu);
int lguest_arch_do_hcall(struct lg_vcpu *vcpu, struct hcall_args *args);
-void lguest_arch_setup_regs(struct lguest *lg, unsigned long start);
+void lguest_arch_setup_regs(struct lg_vcpu *vcpu, unsigned long start);

/* <arch>/switcher.S: */
extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
diff --git a/drivers/lguest/lguest_user.c b/drivers/lguest/lguest_user.c
index abae008..cd68446 100644
--- a/drivers/lguest/lguest_user.c
+++ b/drivers/lguest/lguest_user.c
@@ -108,6 +108,19 @@ static int vcpu_start(struct lg_vcpu *vcpu, int vcpu_id,
/* The timer for lguest's clock needs initialization. */
init_clockdev(vcpu);

+ /* We need a complete page for the Guest registers: they are accessible
+ * to the Guest and we can only grant it access to whole pages. */
+ vcpu->regs_page = get_zeroed_page(GFP_KERNEL);
+ if (!vcpu->regs_page)
+ return -ENOMEM;
+
+ /* We actually put the registers at the bottom of the page. */
+ vcpu->regs = (void *)vcpu->regs_page + PAGE_SIZE - sizeof(*vcpu->regs);
+
+ /* Now we initialize the Guest's registers, handing it the start
+ * address. */
+ lguest_arch_setup_regs(vcpu, start_ip);
+
vcpu->lg = container_of((vcpu - vcpu_id), struct lguest, vcpus[0]);
vcpu->lg->nr_vcpus++;

@@ -166,16 +179,6 @@ static int initialize(struct file *file, const unsigned long __user *input)
if (err)
goto release_guest;

- /* We need a complete page for the Guest registers: they are accessible
- * to the Guest and we can only grant it access to whole pages. */
- lg->regs_page = get_zeroed_page(GFP_KERNEL);
- if (!lg->regs_page) {
- err = -ENOMEM;
- goto release_guest;
- }
- /* We actually put the registers at the bottom of the page. */
- lg->regs = (void *)lg->regs_page + PAGE_SIZE - sizeof(*lg->regs);
-
/* Initialize the Guest's shadow page tables, using the toplevel
* address the Launcher gave us. This allocates memory, so can
* fail. */
@@ -183,10 +186,6 @@ static int initialize(struct file *file, const unsigned long __user *input)
if (err)
goto free_regs;

- /* Now we initialize the Guest's registers, handing it the start
- * address. */
- lguest_arch_setup_regs(lg, args[3]);
-
/* We keep a pointer to the Launcher task (ie. current task) for when
* other Guests want to wake this one (inter-Guest I/O). */
lg->tsk = current;
@@ -211,7 +210,7 @@ static int initialize(struct file *file, const unsigned long __user *input)
return sizeof(args);

free_regs:
- free_page(lg->regs_page);
+ free_page(lg->vcpus[0].regs_page);
release_guest:
kfree(lg);
unlock:
@@ -286,9 +285,12 @@ static int close(struct inode *inode, struct file *file)
/* We need the big lock, to protect from inter-guest I/O and other
* Launchers initializing guests. */
mutex_lock(&lguest_lock);
- for (i = 0; i < lg->nr_vcpus; i++)
+ for (i = 0; i < lg->nr_vcpus; i++) {
/* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */
hrtimer_cancel(&lg->vcpus[i].hrt);
+ /* We can free up the register page we allocated. */
+ free_page(lg->vcpus[i].regs_page);
+ }
/* Free up the shadow page tables for the Guest. */
free_guest_pagetable(lg);
/* Now all the memory cleanups are done, it's safe to release the
@@ -298,8 +300,6 @@ static int close(struct inode *inode, struct file *file)
* kmalloc()ed string, either of which is ok to hand to kfree(). */
if (!IS_ERR(lg->dead))
kfree(lg->dead);
- /* We can free up the register page we allocated. */
- free_page(lg->regs_page);
/* We clear the entire structure, which also marks it as free for the
* next user. */
memset(lg, 0, sizeof(*lg));
diff --git a/drivers/lguest/page_tables.c b/drivers/lguest/page_tables.c
index c79fac2..5045325 100644
--- a/drivers/lguest/page_tables.c
+++ b/drivers/lguest/page_tables.c
@@ -641,6 +641,7 @@ void map_switcher_in_guest(struct lg_vcpu *vcpu,
pte_t *switcher_pte_page = __get_cpu_var(switcher_pte_pages);
pgd_t switcher_pgd;
pte_t regs_pte;
+ unsigned long pfn;

/* Make the last PGD entry for this Guest point to the Switcher's PTE
* page for this CPU (with appropriate flags). */
@@ -655,7 +656,8 @@ void map_switcher_in_guest(struct lg_vcpu *vcpu,
* CPU's "struct lguest_pages": if we make sure the Guest's register
* page is already mapped there, we don't have to copy them out
* again. */
- regs_pte = pfn_pte (__pa(lg->regs_page) >> PAGE_SHIFT, __pgprot(_PAGE_KERNEL));
+ pfn = __pa(vcpu->regs_page) >> PAGE_SHIFT;
+ regs_pte = pfn_pte(pfn, __pgprot(_PAGE_KERNEL));
switcher_pte_page[(unsigned long)pages/PAGE_SIZE%PTRS_PER_PTE] = regs_pte;
}
/*:*/
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index b336fff..f213d00 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -129,7 +129,7 @@ static void run_guest_once(struct lg_vcpu *vcpu,
/* Set the trap number to 256 (impossible value). If we fault while
* switching to the Guest (bad segment registers or bug), this will
* cause us to abort the Guest. */
- lg->regs->trapnum = 256;
+ vcpu->regs->trapnum = 256;

/* Now: we push the "eflags" register on the stack, then do an "lcall".
* This is how we change from using the kernel code segment to using
@@ -197,11 +197,11 @@ void lguest_arch_run_guest(struct lg_vcpu *vcpu)
* bad virtual address. We have to grab this now, because once we
* re-enable interrupts an interrupt could fault and thus overwrite
* cr2, or we could even move off to a different CPU. */
- if (lg->regs->trapnum == 14)
+ if (vcpu->regs->trapnum == 14)
lg->arch.last_pagefault = read_cr2();
/* Similarly, if we took a trap because the Guest used the FPU,
* we have to restore the FPU it expects to see. */
- else if (lg->regs->trapnum == 7)
+ else if (vcpu->regs->trapnum == 7)
math_state_restore();

/* Restore SYSENTER if it's supposed to be on. */
@@ -227,12 +227,12 @@ static int emulate_insn(struct lg_vcpu *vcpu)
unsigned int insnlen = 0, in = 0, shift = 0;
/* The eip contains the *virtual* address of the Guest's instruction:
* guest_pa just subtracts the Guest's page_offset. */
- unsigned long physaddr = guest_pa(lg, lg->regs->eip);
+ unsigned long physaddr = guest_pa(lg, vcpu->regs->eip);

/* This must be the Guest kernel trying to do something, not userspace!
* The bottom two bits of the CS segment register are the privilege
* level. */
- if ((lg->regs->cs & 3) != GUEST_PL)
+ if ((vcpu->regs->cs & 3) != GUEST_PL)
return 0;

/* Decoding x86 instructions is icky. */
@@ -275,12 +275,12 @@ static int emulate_insn(struct lg_vcpu *vcpu)
if (in) {
/* Lower bit tells is whether it's a 16 or 32 bit access */
if (insn & 0x1)
- lg->regs->eax = 0xFFFFFFFF;
+ vcpu->regs->eax = 0xFFFFFFFF;
else
- lg->regs->eax |= (0xFFFF << shift);
+ vcpu->regs->eax |= (0xFFFF << shift);
}
/* Finally, we've "done" the instruction, so move past it. */
- lg->regs->eip += insnlen;
+ vcpu->regs->eip += insnlen;
/* Success! */
return 1;
}
@@ -289,12 +289,12 @@ static int emulate_insn(struct lg_vcpu *vcpu)
void lguest_arch_handle_trap(struct lg_vcpu *vcpu)
{
struct lguest *lg = vcpu->lg;
- switch (lg->regs->trapnum) {
+ switch (vcpu->regs->trapnum) {
case 13: /* We've intercepted a General Protection Fault. */
/* Check if this was one of those annoying IN or OUT
* instructions which we need to emulate. If so, we just go
* back into the Guest after we've done it. */
- if (lg->regs->errcode == 0) {
+ if (vcpu->regs->errcode == 0) {
if (emulate_insn(vcpu))
return;
}
@@ -309,7 +309,8 @@ void lguest_arch_handle_trap(struct lg_vcpu *vcpu)
*
* The errcode tells whether this was a read or a write, and
* whether kernel or userspace code. */
- if (demand_page(lg, lg->arch.last_pagefault, lg->regs->errcode))
+ if (demand_page(lg, lg->arch.last_pagefault,
+ vcpu->regs->errcode))
return;

/* OK, it's really not there (or not OK): the Guest needs to
@@ -340,19 +341,19 @@ void lguest_arch_handle_trap(struct lg_vcpu *vcpu)
case LGUEST_TRAP_ENTRY:
/* Our 'struct hcall_args' maps directly over our regs: we set
* up the pointer now to indicate a hypercall is pending. */
- vcpu->hcall = (struct hcall_args *)lg->regs;
+ vcpu->hcall = (struct hcall_args *)vcpu->regs;
return;
}

/* We didn't handle the trap, so it needs to go to the Guest. */
- if (!deliver_trap(vcpu, lg->regs->trapnum))
+ if (!deliver_trap(vcpu, vcpu->regs->trapnum))
/* If the Guest doesn't have a handler (either it hasn't
* registered any yet, or it's one of the faults we don't let
* it handle), it dies with a cryptic error message. */
kill_guest(lg, "unhandled trap %li at %#lx (%#lx)",
- lg->regs->trapnum, lg->regs->eip,
- lg->regs->trapnum == 14 ? lg->arch.last_pagefault
- : lg->regs->errcode);
+ vcpu->regs->trapnum, vcpu->regs->eip,
+ vcpu->regs->trapnum == 14 ? lg->arch.last_pagefault
+ : vcpu->regs->errcode);
}

/* Now we can look at each of the routines this calls, in increasing order of
@@ -559,9 +560,9 @@ int lguest_arch_init_hypercalls(struct lg_vcpu *vcpu)
*
* Most of the Guest's registers are left alone: we used get_zeroed_page() to
* allocate the structure, so they will be 0. */
-void lguest_arch_setup_regs(struct lguest *lg, unsigned long start)
+void lguest_arch_setup_regs(struct lg_vcpu *vcpu, unsigned long start)
{
- struct lguest_regs *regs = lg->regs;
+ struct lguest_regs *regs = vcpu->regs;

/* There are four "segment" registers which the Guest needs to boot:
* The "code segment" register (cs) refers to the kernel code segment
@@ -588,5 +589,5 @@ void lguest_arch_setup_regs(struct lguest *lg, unsigned long start)

/* There are a couple of GDT entries the Guest expects when first
* booting. */
- setup_guest_gdt(lg);
+ setup_guest_gdt(vcpu->lg);
}
--
1.5.0.6