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Merge branch 'refs/heads/upstream-HEAD' into repo-HEAD
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Delphix Engineering committed Dec 3, 2024
2 parents dc65f95 + 32f5903 commit cab858f
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Showing 29 changed files with 6,041 additions and 116 deletions.
3 changes: 3 additions & 0 deletions NEWS
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Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,9 @@ next
* Support flattened ELF dump files.
* Support partially rearranged makedumpfile split files.
* Parse QEMU CPU state ELF notes.
* Use kernel page tables when initializing X86-64 Linux with PTI from
CR3 register value.
* Fix direct mapping if LDT PTI remapping is used in Linux on X86-64.
* Minor cache improvements and a NULL-pointer dereference fix.
* Fix test suite for 32-bit architectures.

Expand Down
119 changes: 80 additions & 39 deletions src/addrxlat/x86_64.c
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Original file line number Diff line number Diff line change
Expand Up @@ -133,6 +133,9 @@
/** End of direct physical mapping with 5-level paging in 4.2+ */
#define LINUX_DIRECTMAP_END_5L_4_2 0xff90ffffffffffff

/** Linux Page Table Isolation bit in CR3. */
#define LINUX_PTI_USER_PGTABLE_MASK ((addrxlat_addr_t)1 << PAGE_SHIFT)

/** AMD64 (Intel 64) page table step function.
* @param step Current step state.
* @returns Error status.
Expand Down Expand Up @@ -249,7 +252,7 @@ static addrxlat_status
linux_directmap_by_ver(struct sys_region *rgn, unsigned ver)
{
if (ver >= ADDRXLAT_VER_LINUX(4, 8, 0))
return ADDRXLAT_ERR_NOMETH;
return ADDRXLAT_ERR_NOTIMPL;

#define LINUX_DIRECTMAP_BY_VER(a, b, c) \
if (ver >= ADDRXLAT_VER_LINUX(a, b, c)) { \
Expand Down Expand Up @@ -281,6 +284,41 @@ is_directmap(addrxlat_sys_t *sys, addrxlat_ctx_t *ctx,
return status == ADDRXLAT_OK && addr == 0;
}

/** Search for Linux directmap in the page tables.
* @param rgn Directmap region; updated on success.
* @param step Initial state for page table translation.
* @returns Error status.
*/
static addrxlat_status
linux_search_directmap(struct sys_region *rgn, addrxlat_step_t *step)
{
addrxlat_addr_t end;
addrxlat_status status;

if (step->meth->param.pgt.pf.nfields == 6) {
rgn->first = LINUX_DIRECTMAP_START_5L;
end = LINUX_DIRECTMAP_END_5L_4_2;
} else {
rgn->first = LINUX_DIRECTMAP_START_2_6_31;
end = LINUX_DIRECTMAP_END_4_2;
}
while (rgn->first < end) {
status = lowest_mapped(step, &rgn->first, end);
if (status != ADDRXLAT_OK)
break;
if (is_directmap(step->sys, step->ctx, rgn->first)) {
rgn->last = rgn->first;
return highest_linear(step, &rgn->last, end,
-rgn->first);
}
status = lowest_unmapped(step, &rgn->first, end);
if (status != ADDRXLAT_OK)
break;
}

return ADDRXLAT_ERR_NOTIMPL;
}

/** Get directmap location by walking page tables.
* @param rgn Directmap region; updated on success.
* @param sys Translation system object.
Expand All @@ -295,8 +333,6 @@ linux_directmap_by_pgt(struct sys_region *rgn,
addrxlat_sys_t *sys, addrxlat_ctx_t *ctx)
{
addrxlat_step_t step;
addrxlat_addr_t end;
addrxlat_status status;

step.ctx = ctx;
step.sys = sys;
Expand All @@ -314,20 +350,7 @@ linux_directmap_by_pgt(struct sys_region *rgn,
LINUX_DIRECTMAP_END_2_6_11, -rgn->first);
}

if (step.meth->param.pgt.pf.nfields == 6) {
rgn->first = LINUX_DIRECTMAP_START_5L;
end = LINUX_DIRECTMAP_END_5L_4_2;
} else {
rgn->first = LINUX_DIRECTMAP_START_2_6_31;
end = LINUX_DIRECTMAP_END_4_2;
}
status = lowest_mapped(&step, &rgn->first, end);
if (status == ADDRXLAT_OK) {
rgn->last = rgn->first;
return highest_linear(&step, &rgn->last, end, -rgn->first);
}

return ADDRXLAT_ERR_NOTIMPL;
return linux_search_directmap(rgn, &step);
}

/** Set up Linux direct mapping on x86_64.
Expand All @@ -340,6 +363,9 @@ linux_directmap(struct os_init_data *ctl)
struct sys_region layout[2];
addrxlat_status status;

if (ctl->sys->meth[ADDRXLAT_SYS_METH_DIRECT].kind != ADDRXLAT_NOMETH)
return ADDRXLAT_OK;

status = linux_directmap_by_pgt(&layout[0], ctl->sys, ctl->ctx);
if (status != ADDRXLAT_OK && opt_isset(ctl->popt, version_code))
status = linux_directmap_by_ver(&layout[0],
Expand All @@ -350,10 +376,8 @@ linux_directmap(struct os_init_data *ctl)
layout[0].act = SYS_ACT_DIRECT;
layout[1].meth = ADDRXLAT_SYS_METH_NUM;
status = sys_set_layout(ctl, ADDRXLAT_SYS_MAP_KV_PHYS, layout);
if (status != ADDRXLAT_OK)
return status;
}
return ADDRXLAT_OK;
return status;
}

/** Set the kernel text mapping offset.
Expand Down Expand Up @@ -691,46 +715,64 @@ set_xen_p2m(struct os_init_data *ctl)
}

/** Get the top-level page table address for a Linux kernel.
* @param ctx Address translation object.
* @param addr Root page table address. Updated on success.
* @param ctl Initialization data.
* @returns Error status.
*
* It is not an error if the root page table address cannot be
* determined; it merely stays uninitialized.
*/
static addrxlat_status
get_linux_pgt_root(addrxlat_ctx_t *ctx, addrxlat_fulladdr_t *addr)
get_linux_pgt_root(struct os_init_data *ctl)
{
static const char err_fmt[] = "Cannot resolve \"%s\"";
addrxlat_fulladdr_t *addr;
addrxlat_status status;

addr = &ctl->sys->meth[ADDRXLAT_SYS_METH_PGT].param.pgt.root;
if (addr->as != ADDRXLAT_NOADDR)
return ADDRXLAT_OK;

status = get_symval(ctx, "init_top_pgt", &addr->addr);
status = get_reg(ctl->ctx, "cr3", &addr->addr);
if (status == ADDRXLAT_OK) {
addr->addr &= ~PAGE_MASK;
addr->as = ADDRXLAT_MACHPHYSADDR;
if (!(addr->addr & LINUX_PTI_USER_PGTABLE_MASK))
return status;
status = linux_directmap(ctl);
if (status == ADDRXLAT_ERR_NOTIMPL) {
addr->addr &= ~LINUX_PTI_USER_PGTABLE_MASK;
status = linux_directmap(ctl);
if (status == ADDRXLAT_OK)
return status;
addr->addr |= LINUX_PTI_USER_PGTABLE_MASK;
}
} else if (status != ADDRXLAT_ERR_NODATA)
return set_error(ctl->ctx, status, err_fmt, "cr3");
clear_error(ctl->ctx);

status = get_symval(ctl->ctx, "swapper_pg_dir", &addr->addr);
if (status == ADDRXLAT_OK) {
addr->as = ADDRXLAT_KVADDR;
return status;
} else if (status != ADDRXLAT_ERR_NODATA)
return set_error(ctx, status, err_fmt, "init_top_pgt");
clear_error(ctx);
return set_error(ctl->ctx, status, err_fmt, "swapper_pg_dir");
clear_error(ctl->ctx);

status = get_symval(ctx, "init_level4_pgt", &addr->addr);
status = get_symval(ctl->ctx, "init_top_pgt", &addr->addr);
if (status == ADDRXLAT_OK) {
addr->as = ADDRXLAT_KVADDR;
return status;
} else if (status != ADDRXLAT_ERR_NODATA)
return set_error(ctx, status, err_fmt, "init_level4_pgt");
clear_error(ctx);
return set_error(ctl->ctx, status, err_fmt, "init_top_pgt");
clear_error(ctl->ctx);

status = get_reg(ctx, "cr3", &addr->addr);
status = get_symval(ctl->ctx, "init_level4_pgt", &addr->addr);
if (status == ADDRXLAT_OK) {
addr->addr &= ~PAGE_MASK;
addr->as = ADDRXLAT_MACHPHYSADDR;
addr->as = ADDRXLAT_KVADDR;
return status;
} else if (status != ADDRXLAT_ERR_NODATA)
return set_error(ctx, status, err_fmt, "cr3");
clear_error(ctx);
return set_error(ctl->ctx, status, err_fmt, "init_level4_pgt");
clear_error(ctl->ctx);

return ADDRXLAT_OK;
}
Expand All @@ -742,21 +784,20 @@ get_linux_pgt_root(addrxlat_ctx_t *ctx, addrxlat_fulladdr_t *addr)
static addrxlat_status
map_linux_x86_64(struct os_init_data *ctl)
{
addrxlat_meth_t *meth;
addrxlat_addr_t sme_mask;
unsigned long read_caps;
addrxlat_status status;

/* Set up page table translation. */
meth = &ctl->sys->meth[ADDRXLAT_SYS_METH_PGT];
status = get_linux_pgt_root(ctl->ctx, &meth->param.pgt.root);
status = get_linux_pgt_root(ctl);
if (status != ADDRXLAT_OK)
return set_error(ctl->ctx, status,
"Cannot determine root page table");

status = get_number(ctl->ctx, "sme_mask", &sme_mask);
if (status == ADDRXLAT_OK)
meth->param.pgt.pte_mask = sme_mask;
ctl->sys->meth[ADDRXLAT_SYS_METH_PGT].param.pgt.pte_mask =
sme_mask;
else if (status == ADDRXLAT_ERR_NODATA)
clear_error(ctl->ctx);
else
Expand Down Expand Up @@ -796,7 +837,7 @@ map_linux_x86_64(struct os_init_data *ctl)

/* Set up direct mapping. */
status = linux_directmap(ctl);
if (status != ADDRXLAT_OK)
if (status != ADDRXLAT_OK && status != ADDRXLAT_ERR_NOTIMPL)
return status;

return ADDRXLAT_OK;
Expand Down
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